histograms.xml

<!--
Copyright 2020 The Chromium Authors
Use of this source code is governed by a BSD-style license that can be
found in the LICENSE file.
-->

<!--
This file is used to generate a comprehensive list of Blink histograms
along with a detailed description for each histogram.

For best practices on writing histogram descriptions, see
https://chromium.googlesource.com/chromium/src.git/+/HEAD/tools/metrics/histograms/README.md

Please follow the instructions in the OWNERS file in this directory to find a
reviewer. If no OWNERS file exists, please consider signing up at
go/reviewing-metrics (Googlers only), as all subdirectories are expected to
have an OWNERS file. As a last resort you can send the CL to
chromium-metrics-reviews@google.com.
-->

<histogram-configuration>

<histograms>

<variants name="BlinkIncrementalDecodeImageTypes">
  <variant name=".Jpeg"
      summary="Byte size of JPEG images that fall into this category."/>
  <variant name=".WebP"
      summary="Byte size of WebP images that fall into this category."/>
</variants>

<variants name="BlinkVisibleLoadTimeSuffixes">
  <variant name=".2G" summary="2G effective connection type"/>
  <variant name=".3G" summary="3G effective connection type"/>
  <variant name=".4G" summary="4G effective connection type"/>
  <variant name=".Offline" summary="Offline effective connection type"/>
  <variant name=".Slow2G" summary="Slow-2G effective connection type"/>
  <variant name=".Unknown" summary="Unknown effective connection type"/>
</variants>

<variants name="ResourceCacheLifecycleState">
  <variant name="Frozen"/>
  <variant name="Paused"/>
  <variant name="Running"/>
  <variant name="Unknown"/>
</variants>

<variants name="ResourceType">
  <variant name="Audio" summary="Audio"/>
  <variant name="CSSStyleSheet" summary="CSS Style Sheet"/>
  <variant name="Dictionary" summary="Dictionary"/>
  <variant name="Font" summary="Font"/>
  <variant name="Image" summary="Image"/>
  <variant name="LinkPrefetch" summary="Link Prefetch"/>
  <variant name="Manifest" summary="Manifest"/>
  <variant name="Mock" summary="Mock"/>
  <variant name="Raw" summary="Raw"/>
  <variant name="Script" summary="Script"/>
  <variant name="SpeculationRules" summary="Speculation Rules"/>
  <variant name="SVGDocument" summary="SVG Document"/>
  <variant name="TextTrack" summary="Text Track"/>
  <variant name="Video" summary="Video"/>
  <variant name="XSLStyleSheet" summary="XSL Style Sheet"/>
</variants>

<histogram name="Blink.Accessibility.NumTreeUpdatesQueuedBeforeLayout"
    units="updates" expires_after="2023-03-05">
  <owner>aleventhal@chromium.org</owner>
  <owner>chrome-a11y-core@chromium.org</owner>
  <summary>
    Records how many tree updates were queued at the time updates are being
    processed after layout. If we are trying to process too many updates at
    once, we should investigate how we might be able to merge similar updates
    without losing important information.
  </summary>
</histogram>

<histogram base="true" name="Blink.Accessibility.UpdateTime"
    units="microseconds" expires_after="2023-10-08">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>ikilpatrick@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent updating accessibility in the Blink document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true"
    name="Blink.AnchorElementMetricsIntersectionObserver.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle where the observation is for gathering information about anchor
    elements within the visible viewport. Recorded when an intersection
    observation attributed to anchor element metrics is updated.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.Animate.UpdateTime" units="microseconds"
    expires_after="2023-11-12">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent processing main frame animations during a main frame update.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note that the histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes
    before 105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful
    when aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Animation.CompositedAnimationFailureReason"
    enum="CompositorAnimationsFailureReason" expires_after="2023-10-01">
  <owner>smcgruer@chromium.org</owner>
  <owner>animations-dev@chromium.org</owner>
  <summary>
    Reasons an Animation is not suitable for running on the compositor thread.

    Note that a given Animation may have more than one reason, so this histogram
    cannot be used to determine the overall rate of 'composited' vs
    'noncomposited' animations.
  </summary>
</histogram>

<histogram name="Blink.AutomaticLazyFrameLoad.Reason"
    enum="AutomaticLazyFrameLoadReason" expires_after="2023-06-25">
  <owner>sisidovski@chromium.org</owner>
  <owner>chikamune@chromium.org</owner>
  <owner>kouhei@chromium.org</owner>
  <summary>
    Records if the frame is eligible for automatic lazy-load mechanisms. This is
    recorded when each frame having a url in the page is created.
  </summary>
</histogram>

<histogram name="Blink.AutomaticLazyLoadFrame"
    enum="AutomaticLazyLoadFrameState" expires_after="2023-08-27">
  <owner>sisidovski@google.com</owner>
  <owner>kouhei@chromium.org</owner>
  <summary>
    Records if the automatic lazy-load for selected performance problematic
    iframes is applied or not. This is recorded when each frame having a url in
    the page is created. See HTMLFrameOwnerElement::LazyLoadIfPossible() for
    more details.

    Note: There are two groups that lazy-load isn't applied. One group is simply
    the feature itself is disabled, another groupd is that feature is enabled,
    but there are no targeted frames on the page.
  </summary>
</histogram>

<histogram name="Blink.Canvas.2DLayerBridge.Compression.DecompressionTime"
    units="ms" expires_after="2023-10-08">
  <owner>lizeb@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    When a compressed hibernated 2D canvas snapshot is decompressed, duration in
    ms. Reported each time a canvas snapshot is decompressed.
  </summary>
</histogram>

<histogram name="Blink.Canvas.2DLayerBridge.Compression.Ratio" units="%"
    expires_after="2023-10-08">
  <owner>lizeb@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    When a hibernated 2D canvas snapshot is compressed, the compression ratio
    achieved. Reported each time a canvas snapshot is compressed.
  </summary>
</histogram>

<histogram name="Blink.Canvas.2DLayerBridge.Compression.SnapshotSizeKb"
    units="KB" expires_after="2023-10-08">
  <owner>lizeb@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    When a hibernated 2D canvas snapshot is compressed, the size before
    compression. Reported each time a canvas snapshot is compressed.
  </summary>
</histogram>

<histogram name="Blink.Canvas.2DLayerBridge.WillReadFrequently"
    enum="BooleanWillReadFrequently" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>junov@chromium.org</owner>
  <summary>
    Records the state of the willReadFrequently flag upon creation of a Canvas2D
    layer bridge, as this is the moment when it determines whether the canvas
    will be accelerated.
  </summary>
</histogram>

<histogram name="Blink.Canvas.2DPrintingAsVector" enum="BooleanSuccess"
    expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>juanmihd@chromium.org</owner>
  <summary>
    Records if a Canvas is being printed as a vector or as an image.
  </summary>
</histogram>

<histogram name="Blink.Canvas.CanvasColorCache.Effectiveness" units="%"
    expires_after="2024-04-01">
  <owner>sky@chromium.org</owner>
  <owner>junov@chromium.org</owner>
  <summary>
    Records the effectiveness of the canvas color cache. The value is a
    percentage of requests for a color where the color was in the cache. For
    example, a value of 25% means 1 out of every 4 requests for a color was
    available. As this code may be called extensively, the value is logged on
    every 1000th request to the cache. This means the last 0-999 values are not
    recorded, and similarly, if the cache is accessed less than 1000 times
    nothing is logged.
  </summary>
</histogram>

<histogram name="Blink.Canvas.ContentChangeMode"
    enum="BooleanContentChangeMode" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records whether the contents in the canvas buffer needed to be preserved via
    a copy when replacing the target buffer for drawing a new frame. This metric
    is recorded each time the target buffer needs to be replaced. It's recorded
    once per frame.
  </summary>
</histogram>

<histogram name="Blink.Canvas.CreateImageBitmapSource"
    enum="CanvasCreateImageBitmapSource" expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    The source from which an ImageBitmap is created by a createImageBitmap call.
  </summary>
</histogram>

<histogram name="Blink.Canvas.GetImageData.WillReadFrequently"
    enum="BooleanWillReadFrequently" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>junov@chromium.org</owner>
  <summary>
    Records the state of the willReadFrequently flag during Canvas2D readback.
  </summary>
</histogram>

<histogram name="Blink.Canvas.GPUFallbackToCPU"
    enum="CanvasGPUFallbackToCPUScenario" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>Logs the occurrences of canvas fallback from GPU to CPU.</summary>
</histogram>

<histogram name="Blink.Canvas.HasRendered" enum="Boolean"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records if the canvas has been rendered at least once. Recorded on disposal.
  </summary>
</histogram>

<histogram name="Blink.Canvas.HibernationEvents" enum="CanvasHibernationEvent"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records the occurrence of events related to 2D canvas GPU resource
    hibernation.
  </summary>
</histogram>

<histogram name="Blink.Canvas.MaximumInflightResources"
    units="canvas resources" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Reports the maximum number or canvas resources used at any one time by a
    canvas resource provider. Logged in the destructor of
    CanvasResourceProvider.
  </summary>
</histogram>

<histogram name="Blink.Canvas.MaximumStateStackDepth" units="stack depth"
    expires_after="2024-04-01">
  <owner>junov@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Reports the maximum depth of the state stack over the lifetime of a 2d
    rendering context. Metric is recorded once per instance of
    CanvasRenderingContext2D, OffscreenRenderingContext2D, and
    PaintRenderingContext2D; at context destruction time.
  </summary>
</histogram>

<histogram name="Blink.Canvas.NumCanvasesPerPage" units="canvases"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    When a Document is shutdown, reports the number of canvases on that page.
  </summary>
</histogram>

<histogram name="Blink.Canvas.OverdrawOp" enum="CanvasOverdrawOp"
    expires_after="2024-04-01">
  <owner>junov@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Counts 2d canvas draw operations that trigger the overdraw optimization.
  </summary>
</histogram>

<histogram name="Blink.Canvas.RasterDuration{BlinkCanvasRasterDurationType}"
    units="microseconds" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records the CPU, GPU and combined raster time for a random sampling of
    canvas frames for accelerated and deferred canvases. Records wall time for a
    random sampling of unaccelerated canvases.

    Warning: This metric may include reports from clients with low-resolution
    clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
    will cause this metric to have an abnormal distribution. When considering
    revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
    solution. {BlinkCanvasRasterDurationType}
  </summary>
  <token key="BlinkCanvasRasterDurationType">
    <variant name=""/>
    <variant name=".Accelerated.CPU" summary=""/>
    <variant name=".Accelerated.GPU" summary=""/>
    <variant name=".Accelerated.Total" summary=""/>
    <variant name=".Unaccelerated" summary=""/>
  </token>
</histogram>

<histogram
    name="Blink.Canvas.RequestedImageMimeTypes{CanvasRequestedImageMimeTypeFunctions}"
    enum="RequestedImageMimeType" expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Records the occurence of image file formats passed into toDataURL and toBlob
    functions in canvas. {CanvasRequestedImageMimeTypeFunctions}
  </summary>
  <token key="CanvasRequestedImageMimeTypeFunctions">
    <variant name="_convertToBlobPromise"
        summary="Image formats passed to OffscreenCanvas.convertToBlob
                 (promise)"/>
    <variant name="_toBlobCallback"
        summary="Image formats passed to canvas.toBlob (callback)"/>
    <variant name="_toDataURL"
        summary="Image formats passed to canvas.toDataURL"/>
  </token>
</histogram>

<histogram name="Blink.Canvas.ResourceProviderIsAccelerated"
    enum="BooleanHardwareAccelerated" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>Logs if the canvas resource provider is accelerated or not.</summary>
</histogram>

<histogram name="Blink.Canvas.ResourceProviderType"
    enum="CanvasResourceProviderType" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>Records the type of resource provider used for a canvas.</summary>
</histogram>

<histogram name="Blink.Canvas.ResourceProviderUsage"
    enum="CanvasResourceProviderUsage" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records the requested resource usage for a canvas resource provider.
  </summary>
</histogram>

<histogram name="Blink.Canvas.SqrtNumberOfPixels" units="sqrt(pixels)"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Stores the square root of the number of pixels in a new or resized offscreen
    canvas. Emitted from CanvasRenderingContextHost::RecordCanvasSizeToUMA.
  </summary>
</histogram>

<histogram base="true" name="Blink.Canvas.ToBlob.IdleTaskStatus"
    enum="IdleTaskStatus" expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Records the status of the idle task when finishing a toBlob call.

    In addition, metric values from OffscreenCanvas.convertToBlob API call are
    also gathered into this histogram, because the logic flow is exactly the
    same as canvas.toBlob. It's worth to note that the values can come from idle
    tasks on either main or worker thread.
  </summary>
</histogram>

<histogram name="Blink.Canvas.ToBlob.InitialEncodingDelay.{Type}"
    units="microseconds" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    A new version of &quot;Blink.Canvas.ToBlob.InitiateEncodingDelay&quot;
    (which will be allowed to expire) which allows for times &gt;10ms.

    This metric measures the time spent from initiating image encoding (jpeg or
    png) on idle task to the actual execution time of initiation, as part of a
    canvas.toBlob API call.

    This metric is useful in helping us adjust the IdleTaskStartTimeoutDelay in
    canvas.toBlob. When the initialization idle task is delayed for longer than
    IdleTaskStartTimeoutDelay, the browser will switch to a non-idle task to
    force initialization and encoding to occur on the main thread.

    In addition, metric values from OffscreenCanvas.convertToBlob API call are
    also gathered into this histogram, because the logic flow is exactly the
    same as canvas.toBlob. It's worth to note that the values can come from idle
    tasks on either main or worker thread.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
  </summary>
  <token key="Type">
    <variant name="JPEG"/>
    <variant name="PNG"/>
  </token>
</histogram>

<histogram name="Blink.Canvas.ToBlob.ScaledDuration{BlinkCanvasToBlobType}"
    units="microseconds/sqrt(pixels)" expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Time in microseconds spent on the 2D canvas toBlob API call, divided by the
    square root of the total number of pixels of the canvas.

    In addition, metric values from OffscreenCanvas.convertToBlob API call are
    also gathered into this histogram, because the logic flow is exactly the
    same as canvas.toBlob. It's worth to note that the values can come from idle
    tasks on either main or worker thread.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
    {BlinkCanvasToBlobType}
  </summary>
  <token key="BlinkCanvasToBlobType">
    <variant name=".JPEG" summary=""/>
    <variant name=".PNG" summary=""/>
    <variant name=".WEBP" summary=""/>
  </token>
</histogram>

<histogram name="Blink.Canvas.ToBlob.TotalEncodingDelay.{Type}"
    units="microseconds" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    A new version of &quot;Blink.Canvas.ToBlob.InitiateEncodingDelay&quot;
    (which will be allowed to expire) which allows for times &gt;10ms.

    This metric measures the total time spent on completing encoding all the
    rows of an image (jpeg or png), as part of a canvas.toBlob API call.
    Encoding occurs during one or more idle periods on the main thread and the
    waiting time of the next idle period is included in the measurement. If the
    code has swtiched to force encoding path, we will not measure the delay in
    this metric.

    This metric is useful in helping us adjust the IdleTaskCompleteTimeoutDelay
    in canvas.toBlob. When the encoding idle task is delayed for longer than
    IdleTaskCompleteTimeoutDelay, the browser will switch to a non-idle task to
    force encoding to happen on the main thread.

    In addition, metric values from OffscreenCanvas.convertToBlob API call are
    also gathered into this histogram, because the logic flow is exactly the
    same as canvas.toBlob. It's worth to note that the values can come from idle
    tasks on either main or worker thread.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
  </summary>
  <token key="Type">
    <variant name="JPEG"/>
    <variant name="PNG"/>
  </token>
</histogram>

<histogram
    name="Blink.Canvas.ToDataURLScaledDuration{BlinkCanvasToDataURLMimeType}"
    units="microseconds/sqrt(pixels)" expires_after="2024-04-01">
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Time spent on 2D canvas toDataURL API call divided by the square root of the
    total number of pixels of the image. Smaller is faster.

    The idea behind this unit is that the bigger the area of a canvas the longer
    the operation ToDataURL takes, so we want a way to measure the overall
    performance regardless of the size of the canvas.

    Warning: This metric may include reports from clients with low-resolution
    clocks (i.e. on Windows, ref. |TimeTicks::IsHighResolution()|). Such reports
    will cause this metric to have an abnormal distribution. When considering
    revising this histogram, see UMA_HISTOGRAM_CUSTOM_MICROSECONDS_TIMES for the
    solution. {BlinkCanvasToDataURLMimeType}
  </summary>
  <token key="BlinkCanvasToDataURLMimeType">
    <variant name=".JPEG" summary=""/>
    <variant name=".PNG" summary=""/>
    <variant name=".WEBP" summary=""/>
  </token>
</histogram>

<histogram name="Blink.Canvas.VectorPrintFallbackReason"
    enum="CanvasResourceProviderFlushReason" expires_after="2024-04-01">
  <owner>junov@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    The reason why printing a 2D canvas failed to use vector printing.
  </summary>
</histogram>

<histogram name="Blink.Canvas.WebGPUMaxRecycledResourcesCount"
    units="Recyclable resources" expires_after="2023-11-12">
  <owner>magchen@chromium.org</owner>
  <owner>enga@chromium.org</owner>
  <owner>graphics-dev@chromium.org</owner>
  <summary>
    The maximum number of total unused recyclable WebGPU resources since last
    clean-up. Logged in the WebGPU recyclable resouce clean-up timer function.
  </summary>
</histogram>

<histogram name="Blink.Canvas.WebGPUMaxRecycledResourcesInKB" units="KB"
    expires_after="2023-11-12">
  <owner>magchen@chromium.org</owner>
  <owner>enga@chromium.org</owner>
  <owner>graphics-dev@chromium.org</owner>
  <summary>
    The maximum size of total unused recyclable WebGPU resources in KB since
    last clean-up. Logged in the WebGPU recyclable resouce clean-up timer
    function.
  </summary>
</histogram>

<histogram name="Blink.Canvas.WebGPUStaleResourceCount"
    units="recyclable resources" expires_after="2023-08-27">
  <owner>magchen@chromium.org</owner>
  <owner>enga@chromium.org</owner>
  <owner>graphics-dev@chromium.org</owner>
  <summary>
    The number of stale recyclable WebGPU canvas resources released and logged
    in the WebGPU recyclable resouce clean-up timer function.
  </summary>
</histogram>

<histogram name="Blink.Clipboard.HasTransientUserActivation" enum="Boolean"
    expires_after="2023-08-01">
  <owner>asully@chromium.org</owner>
  <owner>snianu@microsoft.com</owner>
  <owner>chrome-owp-storage@google.com</owner>
  <summary>
    Records if a transient user activation is present or not when the web
    authors execute the async clipboard read/write call.
  </summary>
</histogram>

<histogram name="Blink.ColorGamut.Destination" enum="Gamut" expires_after="M85">
  <owner>brianosman@chromium.org</owner>
  <owner>mcasas@google.com</owner>
  <owner>ccameron@chromium.org</owner>
  <summary>Gamut properties of destination color space.</summary>
</histogram>

<histogram name="Blink.ColorSpace.Destination" enum="Gamma" expires_after="M85">
  <owner>brianosman@chromium.org</owner>
  <owner>mcasas@google.com</owner>
  <owner>ccameron@chromium.org</owner>
  <summary>Gamma properties of destination color space.</summary>
</histogram>

<histogram name="Blink.ColorSpace.Destination.NonlinearFitErrorCombined"
    units="units" expires_after="M85">
  <owner>brianosman@chromium.org</owner>
  <owner>mcasas@google.com</owner>
  <owner>ccameron@chromium.org</owner>
  <summary>
    The L-infinity error (in 8-bit values) of the numerical approximation of
    table-based ICC profile transfer functions for all channels combined, when
    the nonlinear approximation converged.
  </summary>
</histogram>

<histogram base="true" name="Blink.CompositingCommit.UpdateTime"
    units="microseconds" expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating and pushing layers at the end of the paint step in the
    Blink document lifecycle. This is implemented by PaintArtifactCompositor.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.CompositingInputs.UpdateTime"
    units="microseconds" expires_after="2023-10-08">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating compositing inputs in the Blink document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Compression.CompressionStream.Format"
    enum="CompressionStreamsFormat" expires_after="2023-03-26">
  <owner>ricea@chromium.org</owner>
  <owner>yhirano@chromium.org</owner>
  <summary>
    Compression format passed to the constructor of the JavaScript API
    &quot;CompressionStream&quot;, which is used for lossless compression of
    arbitrary binary data. Recorded once per call to the constructor. This
    measures which compression formats are most commonly used in the wild.
  </summary>
</histogram>

<histogram name="Blink.Compression.DecompressionStream.Format"
    enum="CompressionStreamsFormat" expires_after="2023-03-26">
  <owner>ricea@chromium.org</owner>
  <owner>yhirano@chromium.org</owner>
  <summary>
    Compression format passed to the constructor of the JavaScript API
    &quot;DecompressionStream&quot;, which is used for lossless decompression of
    arbitrary binary data. Recorded once per call to the constructor. This
    measures which compression formats are most commonly used in the wild.
  </summary>
</histogram>

<histogram base="true" name="Blink.ContentDocumentUpdate.UpdateTime"
    units="microseconds" expires_after="2023-10-22">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent preparing the document for a canvas draw, SVG image draw or
    plugin during a main frame update. Includes time spent in style update and
    layout.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.ContextMenu.ImageSelection.Depth" units="count"
    expires_after="2023-08-31">
  <owner>flackr@chromium.org</owner>
  <owner>blink-interactions-team@google.com</owner>
  <summary>
    The depth of the discovered image node in the hit test list when performing
    a penetrating image selection search.

    Only recorded when a user long presses or right clicks a document (and an
    image is found).
  </summary>
</histogram>

<histogram name="Blink.ContextMenu.ImageSelection.ElapsedTime"
    units="microseconds" expires_after="2023-08-31">
  <owner>flackr@chromium.org</owner>
  <owner>blink-interactions-team@google.com</owner>
  <summary>
    The amount of time it took to iterate through the dom looking for an image
    node.

    Only recorded when a user long presses or right clicks a document.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
  </summary>
</histogram>

<histogram name="Blink.ContextMenu.ImageSelection.Outcome"
    enum="ImageSelectionOutcome" expires_after="2023-11-12">
  <owner>flackr@chromium.org</owner>
  <owner>blink-interactions-team@google.com</owner>
  <summary>
    The outcome of an image selection search that may or may not trigger the
    context menu.

    Only recorded when a user long presses or right clicks a document (and an
    image is found).
  </summary>
</histogram>

<histogram name="Blink.ContextMenu.ImageSelection.RetrievalOutcome"
    enum="ImageSelectionRetrievalOutcome" expires_after="2023-08-31">
  <owner>flackr@chromium.org</owner>
  <owner>blink-interactions-team@google.com</owner>
  <summary>
    The outcome of a follow up retrieval of an image node after a selection has
    occurred, which occurs asynchronously and thus could be unsuccessful due to
    changes that may occur between the initial hit test and the retrieval.

    Only recorded when a user long presses or right clicks a document (and an
    image is found).
  </summary>
</histogram>

<histogram name="Blink.CSSPaintValue.PaintOffThread"
    enum="BooleanCompositorCSSPaint" expires_after="2022-03-08">
  <owner>xidachen@chromium.org</owner>
  <owner>kevers@chromium.org</owner>
  <summary>
    Records if a CSS Paint is painted on the compositor thread or has fallen
    back to the main thread.
  </summary>
</histogram>

<histogram name="Blink.CSSStyleSheetResource.ParseTime" units="microseconds"
    expires_after="2023-11-12">
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Time spent for parsing the stylesheet. Recorded when the stylesheet finishes
    loading and does not have cached stylesheet contents.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.
  </summary>
</histogram>

<histogram name="Blink.CSSStyleSheetResource.TokenizeTime" units="microseconds"
    expires_after="2023-07-01">
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Time spent for tokenizing the stylesheet. Recorded when the response body of
    the stylesheet is received.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.
  </summary>
</histogram>

<histogram name="Blink.CullRect.UpdateTime" units="microseconds"
    expires_after="2023-10-22">
  <owner>pdr@chromium.org</owner>
  <owner>wangxianzhu@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating the cull rect in the Blink document lifecycle.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.
  </summary>
</histogram>

<histogram name="Blink.DecodedImage.AvifDensity.KiBWeighted"
    units="0.01 bits per pixel" expires_after="2022-10-01">
  <owner>jyrki@google.com</owner>
  <owner>compression-dev@google.com</owner>
  <summary>
    The compressed image size in KiB per image density measured in 0.01 bits per
    pixel. This is logged once per image load after the whole image is loaded
    and only for AVIFs with at least 100 pixels on the smallest dimension (width
    or height). The reported count for a sample represents the image size
    rounded to the nearest KiB.
  </summary>
</histogram>

<histogram name="Blink.DecodedImage.JpegDensity.KiBWeighted"
    units="0.01 bits per pixel" expires_after="2023-10-22">
  <owner>jyrki@google.com</owner>
  <owner>compression-dev@google.com</owner>
  <summary>
    The compressed image size in KiB per image density measured in 0.01 bits per
    pixel. This is logged once per image load after the whole image is loaded
    and only for JPEGs with at least 100 pixels on the smallest dimension (width
    or height). The reported count for a sample represents the image size
    rounded to the nearest KiB.
  </summary>
</histogram>

<histogram name="Blink.DecodedImage.WebPDensity.KiBWeighted"
    units="0.01 bits per pixel" expires_after="2022-10-01">
  <owner>jyrki@google.com</owner>
  <owner>compression-dev@google.com</owner>
  <summary>
    The compressed image size in KiB per image density measured in 0.01 bits per
    pixel. This is logged once per image load after the whole image is loaded
    and only for WebPs with at least 100 pixels on the smallest dimension (width
    or height). The reported count for a sample represents the image size
    rounded to the nearest KiB.
  </summary>
</histogram>

<histogram name="Blink.DecodedImage.WebPFileFormat" enum="WebPFileFormat"
    expires_after="2023-11-12">
  <owner>mcasas@chromium.org</owner>
  <owner>andrescj@chromium.org</owner>
  <summary>
    WebP file format parsed during Blink's header parsing phase (which should
    happen only once per image).
  </summary>
</histogram>

<histogram name="Blink.DecodedImageType" enum="DecodedImageType"
    expires_after="2023-11-12">
  <owner>urvang@chromium.org</owner>
  <summary>
    Image codec inferred during decode. The histogram is incremented when enough
    of the image has been downloaded to infer its width and height. Animated
    images are counted only once, regardless of how many frames there are.
  </summary>
</histogram>

<histogram base="true" name="Blink.DisplayLockIntersectionObserver.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle where the observation is for Display Locking. Recorded when an
    intersection observation is made for the Display Locking reason.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.EffectiveZoom" units="%" expires_after="2023-11-23">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    The EffectiveZoom as reported by ComputedStyle in a Blink renderer. The
    value is reported each time the effective zoom is set to a new value. The
    maximum zoom reported is 400% to keep the histogram of reasonable size.
  </summary>
</histogram>

<histogram name="Blink.Experimental.Cookies.CacheLookupResult2"
    enum="CookieCacheLookupResult" expires_after="2023-11-12">
  <owner>carlscab@google.com</owner>
  <owner>woa-performance@google</owner>
  <summary>
    Whether a GetCookiesString request for a document returned the same result
    as the previous one. This is an experiment to determine the usefulness of a
    cookie cache in the Renderer.

    A sample is recorded for every GetCookiesString request sent from the
    Document owned CookieJar.
  </summary>
</histogram>

<histogram name="Blink.FedCm.ApprovedClientsExistence" enum="Boolean"
    expires_after="2023-12-14">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether an IDP returns an approved clients list in the response.
    Records at most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FedCm.ApprovedClientsSize" units="clients"
    expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the size of the approved clients list returned by IDP if applicable.
    Records at most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FedCm.AutoReauthn.BlockedByContentSettings"
    enum="Boolean" expires_after="2023-10-08">
  <owner>npm@chromium.org</owner>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the FedCM auto re-authn call is blocked because the auto
    re-authn content settings permission is disabled. Records at most one sample
    per FedCM API with auto re-authn enabled: some failures could occur before
    this metric is recorded.
  </summary>
</histogram>

<histogram name="Blink.FedCm.AutoReauthn.BlockedByEmbargo" enum="Boolean"
    expires_after="2023-10-08">
  <owner>npm@chromium.org</owner>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the FedCM auto re-authn call is blocked because the auto
    re-authn is under embargo, i.e. due to cooldown. Records at most one sample
    per FedCM API with auto re-authn enabled: some failures could occur before
    this metric is recorded.
  </summary>
</histogram>

<histogram name="Blink.FedCm.AutoReauthn.ReturningAccounts"
    enum="FedCmReturningAccounts" expires_after="2023-10-08">
  <owner>npm@chromium.org</owner>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether there was zero, one, or multiple returning accounts when a
    site calls the FedCM API with autoReauthn: true. Records at most one sample
    per failed API call: some failures could occur before this metric is
    recorded.
  </summary>
</histogram>

<histogram name="Blink.FedCm.AutoReauthn.Succeeded" enum="Boolean"
    expires_after="2023-10-08">
  <owner>npm@chromium.org</owner>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether auto re-authn checks succeeded or not. The count would
    provide roughly the number of FedCM re-authn attempts, the true count would
    provide the number of times the re-authn UI is shown to the user, and the
    false count would provide the number of attempts where auto re-authn was
    blocked for some non-network related reason. Records at most one sample per
    FedCM API with auto re-authn enabled: some failures could occur before this
    metric is recorded.
  </summary>
</histogram>

<histogram name="Blink.FedCm.AutoReauthn.TimeFromEmbargoWhenBlocked" units="ms"
    expires_after="2023-10-08">
  <owner>npm@chromium.org</owner>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the amount of time that has passed from the time the FedCM auto
    re-authn API was embargoed to the time in which the next call occurs. Only
    records a sample when there is an auto re-authn FedCM API call which is
    blocked due to embargo. Samples are exponentially bucketed, with a max
    bucket of 10 minutes, the embargo duration (see
    `kFederatedIdentityAutoReauthnEmbargoDuration`).
  </summary>
</histogram>

<histogram name="Blink.FedCm.CancelReason" enum="FedCmCancelReason"
    expires_after="2023-09-24">
  <owner>pkotwicz@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the reason that the FedCM dialog was closed (ex user clicked the
    dialog close button). Recorded when the FedCM dialog is closed without the
    user selecting an account. This includes instances where the close action is
    less intentional such as the virtual keyboard showing trigerring the dialog
    close.
  </summary>
</histogram>

<histogram name="Blink.FedCm.ClosedSheetType.Android" enum="FedCmSheetType"
    expires_after="2023-11-12">
  <owner>npm@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the type of FedCM Android UI sheet that is being displayed when the
    user manually closes it. Records when the user closes this dialog, so at
    most once per API call that results in UI being shown.
  </summary>
</histogram>

<histogram name="Blink.FedCm.ClosedSheetType.Desktop" enum="FedCmSheetType"
    expires_after="2023-07-16">
  <owner>npm@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the type of FedCM desktop UI sheet that is being displayed when the
    user manually closes it. Records when the user closes this dialog, so at
    most once per API call that results in UI being shown.
  </summary>
</histogram>

<histogram name="Blink.FedCm.CloseVerifySheet.Android" enum="Boolean"
    expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the UI that a user is closing is the verify sheet or not on
    Android. Records at most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FedCm.CloseVerifySheet.Desktop" enum="Boolean"
    expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the UI that a user is closing is the verify sheet or not on
    desktop. Records at most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FedCm.IdpSigninRequestInitiatedByUser"
    enum="BooleanYesNo" expires_after="2023-11-12">
  <owner>cbiesinger@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Whenever we receive an IDP sign-in header (Google-Accounts-SignIn or
    IdP-SignIn-Status: action=signin) in response to a non-worker HTTP request,
    this records whether there was a transient user activation as indicated by
    ResourceRequest::has_user_gesture.
  </summary>
</histogram>

<histogram name="Blink.FedCm.IdpSignoutRequestInitiatedByUser"
    enum="BooleanYesNo" expires_after="2023-11-12">
  <owner>cbiesinger@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Whenever we receive an IDP sign-in header (Google-Accounts-SignOut or
    IdP-SignIn-Status: action=signout) in response to a non-worker HTTP request,
    this records whether there was a transient user activation as indicated by
    ResourceRequest::has_user_gesture.
  </summary>
</histogram>

<histogram name="Blink.FedCm.IsAfterWindowOnload" enum="Boolean"
    expires_after="M120">
  <owner>tanzachary@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the FedCM request is made before or after the start of the
    window onload event. Records once per API call when the
    FedCmMultipleIdentityProviders flag is disabled.
  </summary>
</histogram>

<histogram name="Blink.FedCm.IsSignInUser" enum="Boolean"
    expires_after="2023-10-15">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the user selected account is for sign-in or not. Records at
    most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FedCm.PreventSilentAccessFrameType"
    enum="FedCmPreventSilentAccessFrameType" expires_after="2023-11-10">
  <owner>npm@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the type of frame that invokes preventSilentAccess(). Records only
    when there is an existing FedCM sharing permission on the main frame, and
    some frame in the page invokes the preventSilentAccess() JavaScript call.
    Possible values are: main frame, same-site iframe, and cross-site iframe,
    where the site of the iframe is compared with the site of the main frame.
  </summary>
</histogram>

<histogram name="Blink.FedCm.SignInStatusSetToSignout.NetError"
    enum="NetErrorCodes" expires_after="2023-11-04">
  <owner>npm@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the NetError from the accounts list endpoint. This histogram is only
    recorded when the IDP Sign-In Status of an IDP is marked as signout as a
    result of the accounts list endpoint not returning any accounts.
  </summary>
</histogram>

<histogram name="Blink.FedCm.SignUp.PrivacyPolicyClicked" enum="BooleanHit"
    expires_after="M120">
  <owner>pkotwicz@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Recorded each time that the privacy-policy link in the FedCM prompt is
    clicked.
  </summary>
</histogram>

<histogram name="Blink.FedCm.SignUp.TermsOfServiceClicked" enum="BooleanHit"
    expires_after="M120">
  <owner>pkotwicz@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Recorded each time that the terms-of-service link in the FedCM prompt is
    clicked.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Status.Csp" enum="FedCmCspStatus"
    expires_after="M120">
  <owner>cbiesinger@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>Records the result of CSP checks in the FedCM API.</summary>
</histogram>

<histogram name="Blink.FedCm.Status.IdpSigninMatch"
    enum="FedCmIdpSigninMatchStatus" expires_after="M120">
  <owner>pkotwicz@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the browser's knowledge of whether the user is signed-in to
    the IDP based on observing signin/signout HTTP headers matches the
    information returned by the accounts endpoint. Recorded at most once per
    navigator.credentials.get() call after sending the request to the accounts
    endpoint.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Status.MediationRequirement"
    enum="CredentialManagerMediationRequirement" expires_after="2023-11-10">
  <owner>npm@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the mediation requirement of a request token call to the FedCM API.
    Records a sample when the FedCM call is completed, i.e. at the same time as
    Blink.FedCm.Status.RequestIdToken.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Status.RequestIdToken"
    enum="FedCmRequestIdTokenStatus" expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the status of a request token call to the FedCM API.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Status.Revoke" enum="FedCmRevokeStatus"
    expires_after="M110">
  <obsolete>
    Revoke is deprecated. Removed in June 2022.
  </obsolete>
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>Records the status of a revoke call to the FedCM API.</summary>
</histogram>

<histogram name="Blink.FedCm.Status.SignInStateMatch"
    enum="FedCmSignInStateMatchStatus" expires_after="2023-10-15">
  <owner>tanzachary@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether user sign-in states between IDP and browser match. Records a
    sample after browser receives an account list from IDP prior to showing UI.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.CancelOnDialog" units="ms"
    expires_after="2023-10-22">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when the accounts dialog is shown to when the user
    explicitly closes the dialog without selecting any account. Only records a
    sample when the user sees and *explicitly* closes the dialog. For instance,
    the accounts dialog being closed as a result of the user focusing a
    different part of the browser UI does not count as explicitly closing the
    dialog.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.ContinueOnDialog" units="ms"
    expires_after="2023-10-15">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when the accounts dialog is shown to when the user
    presses the Continue button. Only records a sample when the user sees and
    taps the &quot;Continue&quot; button on the dialog.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.IdTokenResponse" units="ms"
    expires_after="2023-07-16">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when the user presses the Continue button to when the
    token response is received. Only records a sample when the token response is
    received.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.PostTaskDelayDuration" units="ms"
    expires_after="M120">
  <owner>tanzachary@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when RequestToken is called directly in
    navigator.credentials.get to when RequestToken would be called if invoked
    through a posted task. Records once per API call when the
    FedCmMultipleIdentityProviders flag is disabled and RequestToken is called
    during or after the window onload event. If RequestToken is called before
    the window onload event, Blink.FedCm.Timing.WindowOnloadDelayDuration is
    recorded instead.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.ShowAccountsDialog" units="ms"
    expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when a call to the API was made to when the accounts
    dialog is shown. Only records a sample when the dialog is shown.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.TurnaroundTime" units="ms"
    expires_after="2023-10-15">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the overall time from when the API is called to when the token
    response is received. Only records a sample when the token response is
    received.
  </summary>
</histogram>

<histogram name="Blink.FedCm.Timing.WindowOnloadDelayDuration" units="ms"
    expires_after="M120">
  <owner>tanzachary@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when RequestToken is called directly in
    navigator.credentials.get to when RequestToken would be called if invoked
    through a window onload event listener. Records once per API call when the
    FedCmMultipleIdentityProviders flag is disabled and RequestToken is called
    prior to the start of the window onload event. If RequestToken is called
    during or after the window onload event,
    Blink.FedCm.Timing.PostTaskDelayDuration is recorded instead.
  </summary>
</histogram>

<histogram name="Blink.FedCm.WebContentsVisible" enum="Boolean"
    expires_after="2023-09-17">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the WebContents is visible when the browser is ready to show
    the accounts dialog to the user. Records at most one sample per API call.
  </summary>
</histogram>

<histogram name="Blink.FencedFrame.CreationOrNavigationOutcome"
    enum="FencedFrameCreationOutcome" expires_after="2023-10-08">
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <owner>lbrady@google.com</owner>
  <summary>
    Records creation and navigation outcomes for a fenced frame. This is written
    either when a fenced frame navigates successfully, or when some issue causes
    either the creation or navigation of a fenced frame to stop.
  </summary>
</histogram>

<histogram name="Blink.FencedFrame.FailedSandboxLoadInTopLevelFrame"
    enum="BooleanYesNo" expires_after="2023-10-08">
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <owner>lbrady@google.com</owner>
  <summary>
    If a fenced frame failed to load due to incorrectly set sandbox flags,
    records whether or not the fenced frame was attempting to be created in a
    top-level frame. This is written whenever a fenced frame creation fails due
    to sandbox flags not being permissive enough.
  </summary>
</histogram>

<histogram name="Blink.FencedFrame.IsFrameResizedAfterSizeFrozen"
    enum="BooleanYesNo" expires_after="2023-08-08">
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <owner>lbrady@google.com</owner>
  <summary>
    Records if a fenced frame's size is set after the size had been frozen. The
    size of a fenced frame is frozen once it navigates to a page, and results in
    the inner contents being scaled to fit the new dimensions without telling it
    the frame's new size. This is only logged up to one time throughout a fenced
    frame's life, and will not be logged if the size is never set after being
    frozen.
  </summary>
</histogram>

<histogram name="Blink.FencedFrame.IsOpaqueFrameSizeCoerced"
    enum="BooleanChanged" expires_after="2023-08-08">
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <owner>lbrady@google.com</owner>
  <summary>
    Records whether an opaque-ads fenced frame's size was changed because the
    provided size was not in the list of allowed sizes. This will not log
    anything for a default mode fenced frame. This will log when an opaque-ads
    fenced frame has its size frozen (which is triggered when it navigates to
    its first page).
  </summary>
</histogram>

<histogram name="Blink.FencedFrame.MandatoryUnsandboxedFlagsSandboxed"
    enum="WebSandboxFlags" expires_after="2023-10-08">
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <owner>lbrady@google.com</owner>
  <summary>
    If a fenced frame failed to load due to incorrectly set sandbox flags,
    records which sandbox flags that should be unsandboxed ended up being
    sandboxed, causing the load to fail. This is written whenever a fenced frame
    creation fails due to sandbox flags not being permissive enough. If multiple
    sandbox flags are incorrectly set, it will log every sandbox flag that was
    not set correctly for each failed load.
  </summary>
</histogram>

<histogram name="Blink.Fetch.RequestResourceTime2{Scheme}" units="microseconds"
    expires_after="2023-05-02">
  <owner>cduvall@chromium.org</owner>
  <owner>csharrison@chromium.org</owner>
  <summary>
    The total microseconds spent in ResourceFetcher::requestResource for
    {Scheme}.

    This histogram only records metrics on machines with high-resolution clocks.
  </summary>
  <token key="Scheme">
    <variant name="" summary="all URLs"/>
    <variant name=".Data" summary="data URLs"/>
  </token>
</histogram>

<histogram name="Blink.FetchQueuedPreloadsTime.{FrameType}.{IsInitial}"
    units="ms" expires_after="2023-05-29">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time it takes to fetch queued subresource preloads for a
    document in a {FrameType}. Logged every time preloads need to be fetched
    after the {IsInitial} preload scan.
  </summary>
  <token key="FrameType">
    <variant name="MainFrame"/>
    <variant name="Subframe"/>
  </token>
  <token key="IsInitial">
    <variant name="Initial"/>
    <variant name="NonInitial"/>
  </token>
</histogram>

<histogram name="Blink.Fonts.DecodeTime" units="microseconds"
    expires_after="2023-11-12">
  <owner>gjc@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Time spent for decoding the fonts. Recorded when a font resource creates its
    decoded data. This histogram is only logged in platforms with
    high-resolution clocks.
  </summary>
</histogram>

<histogram name="Blink.Fonts.EmojiClusterBrokenness" units="%"
    expires_after="2022-01-10">
  <owner>drott@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Percentage of emoji clusters of all emoji clusters going through shaping
    calls that are shaped as either .notdef/tofu glyphs or are shapes as more
    than one glyph, which usually indicates that an emoji sequence was not
    shaped correctly due to the emoji font not supporting it. Recorded per
    page/worker and on page unload if the page contained emoji.
  </summary>
</histogram>

<histogram name="Blink.Fonts.VariableFontsRatio"
    enum="WebFontInstantiationResult" expires_after="2023-09-17">
  <owner>drott@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Tracks adoption ratio of variable fonts compared to conventional (in the
    sense of non-variable) web fonts. Recorded at the time of instantiating a
    Skia SkTypeface from the successfully decoded web font blob.
  </summary>
</histogram>

<histogram base="true" name="Blink.ForcedStyleAndLayout.UpdateTime"
    units="microseconds" expires_after="2023-11-12">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing layouts due to Javascript value requests. Specifically,
    time spent in Blink Document::UpdateStyleAndLayout.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Frame.GetCanonicalUrlRendererTime" units="microseconds"
    expires_after="2023-09-03">
  <owner>carlosk@chromium.org</owner>
  <owner>harringtond@chromium.org</owner>
  <owner>feed@chromium.org</owner>
  <summary>
    Android only: The time spent by the renderer main thread to collect and send
    back to the browser process a web page's canonical link. This is recorded
    every time the renderer fulfills a request for this information. This
    histogram is only logged in platforms with high-resolution clocks.
  </summary>
</histogram>

<histogram base="true" name="Blink.HandleInputEvents.UpdateTime"
    units="microseconds" expires_after="2023-10-22">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent processing rAF-aligned input during a main frame update.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.HitTestDocumentUpdate.UpdateTime"
    units="microseconds" expires_after="2023-10-08">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent preparing the document for hit testing during a main frame
    update. It does not compute the actual hit test time, rather the style,
    layout, compositing, etc time to prepare for the test.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.AbortedParseSize" units="bytes"
    expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    Number of bytes after which the html fast-path parser aborted. This does not
    count the bytes the fast-path parser did not look at. We measure this since
    aborting the fast-path and falling back to the normal parser is wasted
    effort. This is recorded after every invocation of Element::setInnerHTML.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.AbortedParseTime2"
    units="microseconds" expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The amount of time the innerHTML fast-path parser took before reaching input
    it could not handle. This is recorded when Element::setInnerHTML is called,
    and at the moment when the input it can't handle is reached.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.ParseResult"
    enum="InnerHTMLFastPathParserParseResult" expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    Captures the result of the innerHTML fast-path parser. This is recorded
    every time Element::setInnerHTML is called and only if the innerHTML
    fast-path parser is enabled.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.SuccessfulParseSize" units="bytes"
    expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    Number of bytes successfully parsed by the innerHTML fast-path parser. This
    is recorded if the innerHTML fast-path parser completes successfully and is
    logged at the end of parsing the content supplied to Element::setInnerHTML.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.SuccessfulParseTime2"
    units="microseconds" expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The time it takes for the innerHTML fast-path parser to complete processing
    text from Element::setInnerHTML. This is recorded if fast-path innerHTML is
    enabled, and completes successfully.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.TotalParseTime2" units="microseconds"
    expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The total time it takes to complete parsing of Element::setInnerHTML. This
    includes the time taken by the fast-path parser (even if it failed). This is
    recorded after every invocation of Element::setInnerHTML.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLFastPathParser.{Type}.CompositeMaskV2"
    enum="InnerHTMLFastPathParserUnsupportedTagType" expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    This is logged if the innerHTML fast-path parser fails because an {Type} tag
    is encountered. This value is an aggregate (bitmask) that identifies which
    {Type} groupings were encountered. Ideally a single bitmask would be logged,
    but the dashboard doesn't deal well with large bitmasks. The individual
    groupings are recorded via one of Blink.HTMLFastPathParser.*.Mask0-3 (* is
    one of UnsupportedContextTag or UnsupportedTag).
  </summary>
  <token key="Type">
    <variant name="UnsupportedContextTag" summary="unsupported context"/>
    <variant name="UnsupportedTag" summary="unsupported"/>
  </token>
</histogram>

<histogram name="Blink.HTMLFastPathParser.{Type}.Mask{MaskBit}V2" units="tags"
    expires_after="2023-12-07">
  <owner>sky@chromium.org</owner>
  <owner>tebbi@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    See description of Blink.HTMLFastPathParser.*.CompositeMask for an overview
    of this including when it is logged. The value is a bitmask that identifies
    which tags were encountered:

    {MaskBit}
  </summary>
  <token key="Type">
    <variant name="UnsupportedContextTag" summary="unsupported context"/>
    <variant name="UnsupportedTag" summary="unsupported"/>
  </token>
  <token key="MaskBit">
    <variant name="0"
        summary="bit 0: img. bit 1: aside. bit 2: u. bit 3: hr. bit 4: h. bit
                 5: em. bit 6: The tag is not a known html tag. bit 7: The
                 tag is a known html tag, but is not categorized."/>
    <variant name="1"
        summary="bit 0: form. bit 1: Any one of article, header, footer, or
                 section. bit 2: nav. bit 3: iframe. bit 4: Any one of table,
                 tr, td, tbody, or th. bit 5: Any of of dl, dt, or dd. bit 6:
                 ins bit 7: blockquote."/>
    <variant name="2"
        summary="bit 0: center. bit 1: small. bit 2: font. bit 3: fieldset.
                 bit 4: textarea. bit 5: time. bit 6: svg. bit7: body."/>
  </token>
</histogram>

<histogram name="Blink.HTMLParsing.ChunkCount4" units="chunks"
    expires_after="2023-09-17">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The number of chunks parsed while loading a page. Each chunk represents a
    piece of the HTML content that can be loaded without blocking or yielding.
    This is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.InputCharacterCount4" units="characters"
    expires_after="2023-09-17">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The number of characters processed while parsing a document during page
    load. This is computed as the sum of all the characters appended to the
    input string sequence for the parser. This is only reported for http/https
    urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.ParsingTimeMax4" units="microseconds"
    expires_after="2023-11-05">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the maximum time used to parse a single chunk before
    being blocked, yielding or completing, in microseconds. This does not
    include time spent executing script. This is only reported for http/https
    urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.ParsingTimeMin4" units="microseconds"
    expires_after="2023-11-12">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the minimum time used to parse a single chunk before
    being blocked, yielding or completing, in microseconds. This does not
    include time spent executing script. This is only reported for http/https
    urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.ParsingTimeTotal4" units="microseconds"
    expires_after="2023-11-05">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the total amount of time spent in the
    HTMLDocumentParser performing parsing, in microseconds. This does not
    include time spent executing script. This is only reported for http/https
    urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.TimeToDeferredPumpTokenizer4"
    units="microseconds" expires_after="2023-11-05">
  <owner>sky@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    The time between when the first content has been received by the
    HTMLDocumentParser and when parsing begins. This is effectively measuring
    the time between when SchedulePumpTokenizer() is called, and when the task
    runs that does the parsing. This is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.TokensParsedAverage4" units="tokens"
    expires_after="2023-11-12">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the average number of tokens parsed across all chunks.
    This is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.TokensParsedMax4" units="tokens"
    expires_after="2023-09-17">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the maximum number of tokens parsed as a chunk. This
    is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.TokensParsedMin4" units="tokens"
    expires_after="2023-09-17">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the minimum number of tokens parsed as a chunk. This
    is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.TokensParsedTotal4" units="tokens"
    expires_after="2023-11-12">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the total number of tokens parsed across all chunks.
    This is only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.YieldedTimeAverage4" units="microseconds"
    expires_after="2023-09-24">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the average time between parsing of two chunks, in
    microseconds. Will not be recorded if only one chunk was parsed. This is
    only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.YieldedTimeMax4" units="microseconds"
    expires_after="2023-11-12">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the maximum time between parsing of two chunks, in
    microseconds. Will not be recorded if only one chunk was parsed. This is
    only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.HTMLParsing.YieldedTimeMin4" units="microseconds"
    expires_after="2023-09-17">
  <owner>masonf@chromium.org</owner>
  <owner>dom-dev@chromium.org</owner>
  <summary>
    While parsing a page, the minimum time between parsing of two chunks, in
    microseconds. Will not be recorded if only one chunk was parsed. This is
    only reported for http/https urls.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.ImageHasMultipleGeneratorClientIds"
    enum="ImageHasMultipleGeneratorClientIds" expires_after="2023-09-10">
  <owner>vmpstr@chromium.org</owner>
  <owner>khushalsagar@chromium.org</owner>
  <summary>
    This histogram records whether an image has been decoded by a single client
    or by multiple clients during decoding. For an image to be decoded, it is
    always requested by a client with a client_id. If an image has been
    requested by multiple clients, it would be decoded more than once. The
    histogram value is recorded at most two times per image (once per bucket).
    There will be overlap for two buckets, but we can get the the number of an
    image decodeded by only one client with the difference between two buckets.
    This helps us to know how often images get duplicated decoding in real life.
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.IncrementalDecodeNeeded"
    enum="IncrementalDecodeNeeded" expires_after="2022-09-15">
  <owner>andrescj@chromium.org</owner>
  <owner>chromeos-gfx@google.com</owner>
  <summary>
    For JPEG and WebP images, whether all image data has been received before
    decoding begins or whether we are still receiving data and will need to send
    partial image data to the decoder and pause/resume decoding until complete.

    It is emitted when the DeferredImageDecoder is about to create the first
    DecodingImageGenerator for an image.
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.Jpeg.Area" units="pixels"
    expires_after="2022-05-01">
  <owner>andrescj@chromium.org</owner>
  <owner>src/third_party/blink/renderer/platform/image-decoders/OWNERS</owner>
  <summary>
    Number of pixels in a decoded JPEG image. Recorded after decoding is done by
    Blink's JPEG decoder (as opposed to, possibly, a hardware decode
    accelerator). Tracking the image area may include degenerate cases, e.g., an
    image with area = 10000 and dimensions = 1x10000. However, it is reasonable
    to assume these cases are relatively rare and the area of the image can
    serve as a proxy of how useful a decode accelerator can be (the larger the
    area, the better).
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.Jpeg.ColorSpace" enum="JpegColorSpace"
    expires_after="2022-11-13">
  <owner>andrescj@chromium.org</owner>
  <owner>mcasas@chromium.org</owner>
  <summary>
    JPEG color space of a decoded image as guessed by libjpeg_turbo. Recorded
    after decoding is done by Blink's JPEG decoder (as opposed to, possibly, a
    hardware decode accelerator). When the color space is YCbCr, the chroma
    subsampling is also recorded.
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.Png.FirstDecode.Area" units="pixels"
    expires_after="2023-10-08">
  <owner>nigeltao@chromium.org</owner>
  <owner>scroggo@google.com</owner>
  <summary>
    Number of pixels in a completely decoded PNG image frame.
    &quot;Complete&quot; and &quot;First&quot; mean the same things as for the
    Blink.ImageDecoders.Png.FirstDecode.Time histogram.
  </summary>
</histogram>

<histogram name="Blink.ImageDecoders.{Type}.{Index}Decode.Time" units="ms"
    expires_after="2023-03-31">
  <owner>nigeltao@chromium.org</owner>
  <owner>scroggo@google.com</owner>
  <summary>
    Time taken to completely decode an image frame of the {Type} file format.
    This includes time spent in codec implementations but excludes time spent
    waiting for the network or file cache to deliver the source bytes.

    For incremental decoding, e.g. the source bytes involve multiple network
    events, only the final event (producing a complete image frame) triggers a
    histogram record, but that record holds the total time spent on that frame.

    Incomplete (partially decoded) image frames (e.g. navigating away from the
    web page before any of its images fully loaded) are not recorded here, but
    they still might be recorded in the separate Blink.DecodedImageType
    histogram if the partial decoding was able to determine width and height.

    An image's frames may be decoded more than once. If so, {Index}
    distinguishes whether every decode of every frame is tracked or just the
    first (not repeated) decode of the first (not later) frame.

    For an example of repeated (not first) decodes, when switching between tabs
    or scrolling a web page, a previously decoded frame may be discarded so that
    the backing memory can be re-used elsewhere. When that image comes back into
    view, its frame may need decoding again.

    For an example of later (not first) frames, animated images may produce
    multiple frames from a single img tag. Looping animations may be able to
    cache all of the decoded frames after the first playthrough but, if too big
    to cache, playing the loop continually may keep adding Every histogram
    records as uncached frames are repeatedly decoded.

    The Every {Index} correlates more with &quot;how much CPU time (which
    correlates with battery consumption) is spent overall in {Type}
    decoding&quot;. The First {Index} correlates more with &quot;how long until
    First Contentful Paint&quot;.
  </summary>
  <token key="Type">
    <variant name="Avif"/>
    <variant name="Bmp"/>
    <variant name="Gif"/>
    <variant name="Ico"/>
    <variant name="Jpeg"/>
    <variant name="Jxl"/>
    <variant name="Png"/>
    <variant name="WebP"/>
  </token>
  <token key="Index">
    <variant name="Every"/>
    <variant name="First"/>
  </token>
</histogram>

<histogram base="true" name="Blink.ImplCompositorCommit.UpdateTime"
    units="microseconds" expires_after="2023-10-08">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating layers in the compositor thread during a
    ProxyMain::BeginMainFrame. It is the actual work time, excluding time spent
    waiting for the compositor thread to begin.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.ImportMap.HasJSONComments" enum="Boolean"
    expires_after="2023-11-12">
  <owner>jbroman@chromium.org</owner>
  <owner>domenic@chromium.org</owner>
  <summary>
    Whether (non-standard) JSON comments occur in an importmap script element.
    Logged each time it is parsed as valid JSON.
  </summary>
</histogram>

<histogram name="Blink.Input.GestureScrollBeginAsCursorControl"
    enum="BooleanSuccess" expires_after="M91">
  <obsolete>
    Cursor Control feature is launched, the metrics is no longer needed. Removed
    in March 2022.
  </obsolete>
  <owner>ctzsm@chromium.org</owner>
  <owner>changwan@chromium.org</owner>
  <owner>input-dev@chromium.org</owner>
  <summary>Records if a GestureScrollBegin is for cursor control.</summary>
</histogram>

<histogram base="true" name="Blink.IntersectionObservation.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true"
    name="Blink.IntersectionObservationInternalCount.UpdateTime" units="count"
    expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>szager@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Number of IntersectionObserver computations for blink-internal consumers
    that were performed during the course of a single main frame.
  </summary>
</histogram>

<histogram base="true"
    name="Blink.IntersectionObservationJavascriptCount.UpdateTime"
    units="count" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>szager@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Number of IntersectionObserver computations for javascript consumers that
    were performed during the course of a single main frame.
  </summary>
</histogram>

<histogram name="Blink.JavaJsBridge.MethodInvocationError"
    enum="JavaJsBridgeMethodInvocationError" expires_after="2023-06-04">
  <owner>torne@chromium.org</owner>
  <owner>src/android_webview/OWNERS</owner>
  <summary>Records the Java/JS bridge method invocation errors.</summary>
</histogram>

<histogram base="true" name="Blink.JavascriptDocumentUpdate.UpdateTime"
    units="microseconds" expires_after="2023-09-10">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent preparing the document to answer a Javascript API query or
    request. Examples include scrool offset requests, queries of layout
    dimensions, SVG path queries, etc. Includes time spent in style update and
    layout, or via EnsurePaintLocationDataValidForNode. Some of these calls may
    be servicing internal needs, but we have no way to disambiguate those from
    JS driven activity.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.JavascriptIntersectionObserver.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle where the observation is due to a Javascript request. Recorded
    when an intersection observation is made for the Javascript reason.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.KeyboardLock.MethodCalled" enum="KeyboardLockMethods"
    expires_after="2023-06-30">
  <owner>joedow@chromium.org</owner>
  <owner>garykac@chromium.org</owner>
  <summary>
    Records each call to the navigator.keyboard{Lock|Unlock} methods.
  </summary>
</histogram>

<histogram name="Blink.Layout.CloneFragmentsForLayoutOverflow"
    units="microseconds" expires_after="2023-10-27">
  <owner>tkent@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent to clone physical fragments, recorded during LayoutOverflow
    computation.
  </summary>
</histogram>

<histogram name="Blink.Layout.RebuildFragmentTreeSpine" units="microseconds"
    expires_after="2023-10-27">
  <owner>tkent@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent to rebuild container physical fragments, recorded on sub-tree
    root layout.
  </summary>
</histogram>

<histogram name="Blink.Layout.UpdateLayerPositionsAfterLayout"
    units="microseconds" expires_after="2023-10-15">
  <owner>pdr@chromium.org</owner>
  <owner>ikilpatrick@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent in PaintLayer::UpdateLayerPositionsAfterLayout.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.
  </summary>
</histogram>

<histogram base="true" name="Blink.Layout.UpdateTime" units="microseconds"
    expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent updating layout in the Blink document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.LazyLoadedImage.Size" units="KB"
    expires_after="2023-10-10">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Total network response size for each lazy loaded image that has loaded. This
    is recorded at the point that the image element completes loading. This
    includes all entries in `Blink.LazyLoadedImageBeforeDocumentOnLoad.Size` as
    well as lazy loaded images that load after document load.
  </summary>
</histogram>

<histogram name="Blink.LazyLoadedImageBeforeDocumentOnLoad.Size" units="KB"
    expires_after="2023-10-10">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Total network response size for each lazy loaded image that has loaded
    before the document has finished loading. This is recorded at the point that
    the image element completes loading.
  </summary>
</histogram>

<histogram base="true" name="Blink.LazyLoadIntersectionObserver.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle where the observation is due to a Lazy Image Loading request.
    Recorded when an intersection observation is made to determine when a lazy
    loaded image should be loaded.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Loading.CachedResponseArrivalAtRenderer"
    units="Milliseconds" expires_after="2023-11-12">
  <owner>yhirano@chromium.org</owner>
  <owner>loadingg-dev@chromium.org</owner>
  <summary>
    The amount of time taken to get a cached response. Recorded when the
    response arrives, and recorded only when both of the response and the code
    cache were cached.
  </summary>
</histogram>

<histogram name="Blink.Loading.CodeCacheArrivalAtRenderer" units="Milliseconds"
    expires_after="2023-11-12">
  <owner>yhirano@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <summary>
    The amount of time taken to get a code cache. Recorded when the response
    arrives, and recorded only when both of the response and the code cache were
    cached.
  </summary>
</histogram>

<histogram name="Blink.LocalFrameRoot.DidReachFirstContentfulPaint"
    units="Boolean" expires_after="2023-10-08">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Reports if a local frame root ever receives a FirstContentfulPaint signal.
    Only recorded for local frame roots that run at least one main frame update.
  </summary>
</histogram>

<histogram name="Blink.LocalFrameRoot.DidReachFirstContentfulPaint.MainFrame"
    units="Boolean" expires_after="2023-10-08">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Reports if the main frame ever receives a FirstContentfulPaint signal. Only
    recorded for main frame local frame roots that run at least one main frame
    update.
  </summary>
</histogram>

<histogram base="true" name="Blink.MainFrame.UpdateTime" units="microseconds"
    expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time between a BeginMainFrame and paint results commit in Blink.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.MediaIntersectionObserver.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing IntersectionObserver observations in the Blink document
    lifecycle where the observation is for a media element. Recorded when an
    intersection observation is made attributed to a media element (such as
    video auto-play).

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.MemoryCache.CrossDocumentCachedResource2"
    enum="ResourceType" expires_after="2023-10-15">
  <owner>gjc@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Type of cached non-static resources reused across Documents when loading a
    new document in the same renderer. Recorded by the ResourceFetcher when a
    resource is requested for a new document and is not static. If the resource
    is available from the memory cache and previously loaded by a different
    document, the resource will be considered as reused. Repetitive requests to
    the same url in a document will be counted only once.

    Warning: an unexpected reorder happened in Apr 2021
    (https://crrev.com/c/2798954). Please do not trust older reports.
  </summary>
</histogram>

<histogram name="Blink.MemoryCache.PageSavedResourceStrongReferenceSize"
    units="count" expires_after="2023-09-01">
  <owner>gjc@chromium.org</owner>
  <owner>blink-network-stack@chromium.org</owner>
  <summary>
    Size of the resource strong references saved to the memory cache. Recorded
    when the user navigates to a newpage under the same origin. Recorded only
    with feature flag MemoryCacheStrongReference.
  </summary>
</histogram>

<histogram name="Blink.MemoryCache.Remote.IsInCache.{Destination}"
    enum="Boolean" expires_after="2023-08-13">
  <owner>bashi@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Records whether a cached response exists in another renderer that has the
    same process isolation policies. Recorded when ResourceFetcher fetches a
    resource from network. This histogram is for `{Destination}` destination.
  </summary>
  <token key="Destination" variants="RequestDestination"/>
</histogram>

<histogram
    name="Blink.MemoryCache.Remote.{Visibility}.{LifecycleState}.IPCRecvDelay"
    units="microseconds" expires_after="2023-08-13">
  <owner>bashi@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Records the time between when a renderer receives an IPC to look for cached
    response and when another renderer receives the response of that IPC. The
    IPC is sent when ResourceFetcher fetches a resource from network. Recorded
    when the renderer receives the response.

    Note: This histogram is not recorded on low-resolution clock clients.
  </summary>
  <token key="Visibility">
    <variant name="Hidden"/>
    <variant name="Visible"/>
  </token>
  <token key="LifecycleState" variants="ResourceCacheLifecycleState"/>
</histogram>

<histogram
    name="Blink.MemoryCache.Remote.{Visibility}.{LifecycleState}.IPCSendDelay"
    units="microseconds" expires_after="2023-08-13">
  <owner>bashi@chromium.org</owner>
  <owner>blink-network-dev@chromium.org</owner>
  <summary>
    Records the time between when a renderer sends an IPC to look for cached
    response and when another renderer receives that IPC. The IPC is sent when
    ResourceFetcher fetches a resource from network. Recorded when the renderer
    receives the response.

    Note: This histogram is not recorded on low-resolution clock clients.
  </summary>
  <token key="Visibility">
    <variant name="Hidden"/>
    <variant name="Visible"/>
  </token>
  <token key="LifecycleState" variants="ResourceCacheLifecycleState"/>
</histogram>

<histogram name="Blink.MemoryCache.RevalidationPolicy.AsyncScript"
    enum="RevalidationPolicy" expires_after="2023-10-15">
  <owner>hiroshige@chromium.org</owner>
  <owner>lizeb@chromium.org</owner>
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <summary>
    RevalidationPolicy used for non-preloading requests of async and defer
    scripts. https://crbug.com/1043679 https://crbug.com/1376866 Warning: this
    histogram was expired from 2021/10/25 to 2022/12/09; data may be missing.
  </summary>
</histogram>

<histogram name="Blink.MemoryCache.RevalidationPolicy.Dead.{ResourceType}"
    enum="RevalidationPolicy" expires_after="2023-10-01">
  <owner>hiroshige@chromium.org</owner>
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <summary>
    RevalidationPolicy used for requests that hit Resource only referenced from
    MemoryCache for each resource type ({ResourceType}).
    https://crbug.com/579496 Requests counted by this are also counted by
    Blink.MemoryCache.RevalidationPolicy or
    Blink.MemoryCache.RevalidationPolicy.Preload. https://crbug.com/1376866

    Warning: this histogram was expired from 2021-04-21 to 2022-12-09; data may
    be missing. This histogram's {ResourceType} was broken until 2023-03-09;
    data before the date may not be stored.
  </summary>
  <token key="ResourceType" variants="ResourceType"/>
</histogram>

<histogram
    name="Blink.MemoryCache.RevalidationPolicy.PerTopFrameSite.{ResourceType}"
    enum="RevalidationPolicy" expires_after="2021-12-26">
  <owner>shivanisha@chromium.org</owner>
  <owner>privacy-sandbox-dev@chromium.org</owner>
  <summary>
    RevalidationPolicy used for requests for each resource type. Logged only if
    the resource is found in the memory cache and if the same top-frame site had
    loaded this resource earlier.
  </summary>
  <token key="ResourceType" variants="ResourceType"/>
</histogram>

<histogram name="Blink.MemoryCache.RevalidationPolicy.Preload.{ResourceType}"
    enum="RevalidationPolicy" expires_after="2023-10-01">
  <owner>hiroshige@chromium.org</owner>
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <summary>
    RevalidationPolicy used for preloading requests for each resource type
    ({ResourceType}). https://crbug.com/579496 https://crbug.com/1376866

    Warning: this histogram was expired from 2021-04-21 to 2022-12-09; data may
    be missing. This histogram's {ResourceType} was broken until 2023-03-09;
    data before the date may not be stored.
  </summary>
  <token key="ResourceType" variants="ResourceType"/>
</histogram>

<histogram name="Blink.MemoryCache.RevalidationPolicy.{ResourceType}"
    enum="RevalidationPolicy" expires_after="2023-10-01">
  <owner>hiroshige@chromium.org</owner>
  <owner>gjc@chromium.org</owner>
  <owner>loading-dev@chromium.org</owner>
  <summary>
    RevalidationPolicy used for non-preloading requests for each resource type.
    https://crbug.com/579496 https://crbug.com/1376866

    Warning: this histogram was expired from 2021-04-21 to 2022-12-09; data may
    be missing. This histogram's {ResourceType} was broken until 2023-03-09;
    data before the date may not be stored.
  </summary>
  <token key="ResourceType" variants="ResourceType"/>
</histogram>

<histogram name="Blink.MobileMetrics.BadTapTargetRatioExtractionSucceed"
    units="Boolean" expires_after="2023-05-07">
  <owner>kumagi@google.com</owner>
  <owner>gaul@google.com</owner>
  <owner>paint-dev@google.com</owner>
  <summary>
    Whether element extraction phase succeed without consuming entire 4ms time
    budget in MobileFriendlinessChecker::ComputeBadTapTargetsRatio() evaluation.
    This metric recorded at 5 seconds after first MainFrame's commit and
    periodically every 1 minutes after that.
  </summary>
</histogram>

<histogram name="Blink.MobileMetrics.BadTapTargetRatioTime"
    units="microseconds" expires_after="2022-12-01">
  <owner>kumagi@google.com</owner>
  <owner>gaul@google.com</owner>
  <owner>paint-dev@google.com</owner>
  <summary>
    The time taken in MobileFriendliness::ComputebadTapTargetsRatio evalution.
    This metric recorded at 5 seconds after first MainFrame's commit and
    periodically every 1 minutes after that.

    The histogram does not record metric on machines with low-resolution clocks.
  </summary>
</histogram>

<histogram name="Blink.Navigator.ReducedUserAgent" enum="Boolean"
    expires_after="2023-08-27">
  <owner>miketaylr@chromium.org</owner>
  <owner>victortan@chromium.org</owner>
  <owner>potassium-katabolism@google.com</owner>
  <summary>
    Whether the navigator.userAgent and navigator.appVersion JavaScript getters
    returned a reduced user agent string value. The reduced user agent string is
    only returned in the presence of a valid UserAgentReduction origin trial
    token. This histogram is recorded when the navigator.userAgent and
    navigator.appVersion JavaScript APIs are invoked.
  </summary>
</histogram>

<histogram name="Blink.NotificationManager.GetPermissionStatusTime" units="ms"
    expires_after="2023-09-17">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    The time taken to query the notification permission status. This is recorded
    each time a sync call is made.
  </summary>
</histogram>

<histogram name="Blink.OffscreenCanvas.NewOffscreenCanvas" enum="Boolean"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records the creation of a new offscreen canvas in OffscreenCanvas::Create.
  </summary>
</histogram>

<histogram name="Blink.OffscreenCanvas.SqrtNumberOfPixels" units="sqrt(pixels)"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Stores the square root of the number of pixels in a new or resized offscreen
    canvas. Emitted from CanvasRenderingContextHost::RecordCanvasSizeToUMA.
  </summary>
</histogram>

<histogram name="Blink.OffscreenCanvas.TransferControlToOffscreen"
    enum="BooleanSuccess" expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>Records a call to transfer a canvas offscreen.</summary>
</histogram>

<histogram name="Blink.OffscreenCanvas.Transferred" enum="Boolean"
    expires_after="2024-04-01">
  <owner>aaronhk@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <summary>
    Records when an offscreen canvas has been transferred from the main thread
    to a worker.
  </summary>
</histogram>

<histogram name="Blink.Overflow.ReplacedElementAreaOutsideContentRect"
    units="pixels" expires_after="2023-11-12">
  <owner>khushalsagar@chromium.org</owner>
  <owner>vmpstr@chromium.org</owner>
  <summary>
    Computes the area of img, video or canvas elements which is painted outside
    the content rect if 'overflow' property is respected on these elements.
  </summary>
</histogram>

<histogram base="true" name="Blink.Paint.UpdateTime" units="microseconds"
    expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating paint in the Blink document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram base="true" name="Blink.ParseStyleSheet.UpdateTime"
    units="microseconds" expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Time spent parsing style sheets for a document. Only recorded when the
    CSSParserContext has a document available.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Plugin.UpdateTime" units="ms" expires_after="2022-12-18">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time it takes to update the plugin list. This can happen, for
    example, during Navigator.plugins.get.
  </summary>
</histogram>

<histogram name="Blink.Prefetch.LinkPrefetchMimeType"
    enum="LinkPrefetchMimeType" expires_after="2023-10-08">
  <owner>jbroman@chromium.org</owner>
  <summary>
    Categorizes MIME types of responses to &quot;prefetch&quot; links. Intended
    to gather data about whether this feature is used mainly for documents,
    subresources, or both. Emitted once per resource fetched (which may be more
    than one per page).
  </summary>
</histogram>

<histogram name="Blink.PreloadRequestWaitTime" units="ms"
    expires_after="2023-10-22">
  <owner>cduvall@chromium.org</owner>
  <owner>swarm-team@google.com</owner>
  <summary>
    Measures the time from the creation of a PreloadRequest to when
    PreloadRequest::Start is called. Logged for each PreloadRequest::Start call.
  </summary>
</histogram>

<histogram base="true" name="Blink.PrePaint.UpdateTime" units="microseconds"
    expires_after="2023-10-01">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating paint properties and paint invalidation in the Blink
    document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.ResourceRequest.CompletionDelay" units="ms"
    expires_after="2023-07-19">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time from when a resource request completes to when the
    renderer is notified. Logged for every resource request.
  </summary>
</histogram>

<histogram name="Blink.ResourceRequest.RedirectDelay" units="ms"
    expires_after="2023-09-17">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time from when a redirect from a resource request happens to
    when the renderer is notified. Logged for every resource request redirect.
  </summary>
</histogram>

<histogram name="Blink.ResourceRequest.ResponseDelay" units="ms"
    expires_after="2023-07-19">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time from when a response from a resource request is started to
    when the renderer is notified. Logged for every resource request.
  </summary>
</histogram>

<histogram name="Blink.ResourceRequest.StartDelay" units="ms"
    expires_after="2023-07-19">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time from when the renderer starts a resource request to when
    it is actually started on the network. Logged for every resource request.
  </summary>
</histogram>

<histogram
    name="Blink.Responsiveness.UserInteraction.MaxEventDuration.{InteractionType}"
    units="ms" expires_after="never">
<!-- expires-never: Supports guardrail metric debugging -->

  <owner>sullivan@chromium.org</owner>
  <owner>mmocny@chromium.org</owner>
  <owner>speed-metrics-dev@chromium.org</owner>
  <summary>
    The duration of a single user interaction:
    https://web.dev/better-responsiveness-metric/#group-events-into-interactions

    This metric is emitted once for every interaction in the web contents
    {InteractionType}
  </summary>
  <token key="InteractionType">
    <variant name="AllTypes"
        summary="of all interaction types (keyboard, click, tap, drag). The
                 maximum event duration for the keydown, keypress, keyup,
                 pointerdown, pointerup, mousedown, mouseup, and click event
                 is reported."/>
    <variant name="Drag"
        summary="of type drag. The maximum event duration for the
                 pointerdown, pointerup, mousedown, mouseup, and click event
                 is reported."/>
    <variant name="Keyboard"
        summary="of type keyboard. The maximum event duration for the
                 keydown, keypress, and keyup event is reported."/>
    <variant name="TapOrClick"
        summary="of type click or tap. The maximum event duration for the
                 pointerdown, pointerup, mousedown, mouseup, and click event
                 is reported."/>
  </token>
</histogram>

<histogram name="Blink.ScanAndPreloadTime.{FrameType}.{IsInitial}" units="ms"
    expires_after="2023-05-29">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time it takes to scan and preload subresources for a document
    in a {FrameType}. Logged every time the {IsInitial} preload scan is
    performed.
  </summary>
  <token key="FrameType">
    <variant name="MainFrame"/>
    <variant name="Subframe"/>
  </token>
  <token key="IsInitial">
    <variant name="Initial"/>
    <variant name="NonInitial"/>
  </token>
</histogram>

<histogram name="Blink.ScanPendingActivityDuration" units="ms"
    expires_after="M85">
  <owner>haraken@chromium.org</owner>
  <summary>
    Duration of time taken to scan pending activities of all V8 wrappers in a
    worker thread.
  </summary>
</histogram>

<histogram name="Blink.Script.AsyncScriptCount" units="count"
    expires_after="2022-04-04">
  <owner>dom@chromium.org</owner>
  <owner>chrome-loading@google.com</owner>
  <summary>
    The total number of async scripts associated with a document at the time
    parsing has finished.
  </summary>
</histogram>

<histogram name="Blink.Script.ForceDeferredScripts.Mainframe" units="count"
    expires_after="2023-12-01">
  <owner>chikamune@chromium.org</owner>
  <owner>hiroshige@chromium.org</owner>
  <owner>sisidovski@chromium.org</owner>
  <summary>
    Number of synchronous scripts that were deferred for a mainframe by the
    ForceDeferScriptIntervention. This includes both inline scripts and external
    scripts that had their execution deferred until after parsing completes.
    Recorded at the end of parsing when ForceDeferScriptIntervention is enabled.
  </summary>
</histogram>

<histogram name="Blink.Script.ForceDeferredScripts.Mainframe.External"
    units="count" expires_after="2023-12-01">
  <owner>chikamune@chromium.org</owner>
  <owner>hiroshige@chromium.org</owner>
  <owner>sisidovski@chromium.org</owner>
  <summary>
    Number of external synchronous scripts that were deferred for a mainframe by
    the ForceDeferScriptIntervention. Recorded at the end of parsing when
    ForceDeferScriptIntervention is enabled.
  </summary>
</histogram>

<histogram name="Blink.Script.ForceDeferredScripts.Subframe" units="count"
    expires_after="2023-12-01">
  <owner>chikamune@chromium.org</owner>
  <owner>hiroshige@chromium.org</owner>
  <owner>sisidovski@chromium.org</owner>
  <summary>
    Number of synchronous scripts that were deferred for a subframe by the
    ForceDeferScriptIntervention. This includes both inline scripts and external
    scripts that had their execution deferred until after parsing completes.
    Recorded at the end of parsing when ForceDeferScriptIntervention is enabled.
  </summary>
</histogram>

<histogram name="Blink.Script.ForceDeferredScripts.Subframe.External"
    units="count" expires_after="2023-12-01">
  <owner>chikamune@chromium.org</owner>
  <owner>hiroshige@chromium.org</owner>
  <owner>sisidovski@chromium.org</owner>
  <summary>
    Number of external synchronous scripts that were deferred for a subframe by
    the ForceDeferScriptIntervention. Recorded at the end of parsing when
    ForceDeferScriptIntervention is enabled.
  </summary>
</histogram>

<histogram name="Blink.Script.SchedulingType" enum="ScriptSchedulingType"
    expires_after="2023-11-12">
  <owner>kouhei@chromium.org</owner>
  <owner>hiroshige@chromium.org</owner>
  <owner>chikamune@chromium.org</owner>
  <summary>
    Number of script elements for each scheduling type, recorded when each
    script loading reaches the #prepare-a-script state defined in the spec, with
    http or https request.

    Warning: this histogram was expired from 2018-12-31 to 2022-05-25; data may
    be missing.
  </summary>
</histogram>

<histogram name="Blink.Script.SourceTextTime" units="microseconds"
    expires_after="2023-08-27">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@google.com</owner>
  <summary>
    The time spent generating the source text for a script resource. Logged when
    the source text is accessed for the first time. Emitted at most once per
    script resource.

    Note that clients without high-resolution clocks will report 0 for very
    short times.
  </summary>
</histogram>

<histogram base="true" name="Blink.ServiceDocumentUpdate.UpdateTime"
    units="microseconds" expires_after="2023-09-10">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent preparing the document to service browser driven behaviors.
    Examples include accessibility, intersection observer, display locking and
    spell checking. Includes time spent in style update and layout.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.Sms.BackendAvailability"
    enum="WebOTPBackendAvailability" expires_after="2023-09-10">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records how often the verification backend is unavailable for the WebOTP API
    and the corresponding reason. This is recorded once per OTP request.
  </summary>
</histogram>

<histogram name="Blink.Sms.PendingOriginCount" units="origins"
    expires_after="2023-11-12">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    SmsFetcher subscribes to incoming SMSes with origins from SmsProvider. This
    metric records the number of pending origins that are not unsubscribed when
    the SmsFetcher subscribes to new origins.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.CrossDeviceFailure"
    enum="WebOTPCrossDeviceFailure" expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the reason why using the WebOTP API on desktop failed on the sharing
    path. It records one sample per invocation of the API.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.Infobar" enum="WebOTPServiceInfobarAction"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records how many times the infobar was called and how many times the infobar
    replaced a keyboard.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.Outcome" enum="WebOTPServiceOutcome"
    expires_after="2023-11-12">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>Records the result of a call to the WebOTP API.</summary>
</histogram>

<histogram name="Blink.Sms.Receive.SmsParsingStatus" enum="SmsParsingStatus"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the status of parsing an incoming SMS when using the WebOTP API. It
    records one sample per incoming SMS.

    Note: This metric does not cover cross-devices WebOTP.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeCancel" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when the API is called to when the request is
    cancelled by the service due to duplicated requests or lack of delegate.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeCancelOnKeyboardDismissal" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when the keyboard was replaced with an infobar
    until when the user clicked the cancel button.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeCancelOnSuccess" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when a successful SMS was retrieved to when the user
    presses the Cancel button.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeContinueOnSuccess" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the time from when a successful SMS was retrieved to when the user
    presses the Continue button.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeSmsReceive" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when the API is called to when an SMS has been
    successfully received.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeSuccess" units="ms"
    expires_after="2023-09-10">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when the API is called to when the user
    successfully receives the SMS and presses continue to pass the incoming SMS
    to the site and proceed with the SMS verification flow.
  </summary>
</histogram>

<histogram name="Blink.Sms.Receive.TimeUserCancel" units="ms"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>goto@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records the duration from when the API is called to when the user
    successfully receives the SMS and presses &quot;Deny&quot; to terminate the
    SMS verification flow.
  </summary>
</histogram>

<histogram name="Blink.Sms.WebContentsVisibleOnReceive" enum="Boolean"
    expires_after="2023-07-09">
  <owner>yigu@chromium.org</owner>
  <owner>web-identity-eng@google.com</owner>
  <summary>
    Records whether the web contents that receives the OTP is visible or not for
    the UserConsent backend. Recorded at most once per API call when Chrome sees
    the OTP from the expected origin.
  </summary>
</histogram>

<histogram name="Blink.SpeculationRules.FetchTime" units="ms"
    expires_after="2023-08-08">
  <owner>jbroman@chromium.org</owner>
  <owner>src/third_party/blink/renderer/core/speculation_rules/OWNERS</owner>
  <summary>
    The amount of time between when a fetch of speculation rules is started and
    when it is finished. Recorded each time such a fetch occurs.
  </summary>
</histogram>

<histogram name="Blink.SpeculationRules.LoadOutcome"
    enum="SpeculationRulesLoadOutcome" expires_after="2023-10-08">
  <owner>jbroman@chromium.org</owner>
  <owner>src/third_party/blink/renderer/core/speculation_rules/OWNERS</owner>
  <summary>
    Outcome of an attempt to load a speculation rule set. Recorded once per
    attempt, whether triggered by a response header, by the parser or by script.
  </summary>
</histogram>

<histogram base="true" name="Blink.Style.UpdateTime" units="microseconds"
    expires_after="2023-10-22">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>layout-dev@chromium.org</owner>
  <summary>
    Time spent updating style in the Blink document lifecycle.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.SVGImage.DataChanged" units="microseconds"
    expires_after="2023-10-22">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent updating a SVG image once all data is received.

    This histogram does not record metrics on machines with low-resolution
    clocks.
  </summary>
</histogram>

<histogram name="Blink.UpdateViewportIntersection.UpdateTime"
    units="microseconds" expires_after="2023-12-11">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent computing geometry information about iframes from the perspective
    of their embedding document. This time is also included in the
    Blink.IntersectionObservation.UpdateTime metric.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.AnimatedCSSProperties"
    enum="MappedCSSProperties" expires_after="never">
<!-- expires-never: used by Chrome Platform Status dashboard -->

<!-- https://www.chromestatus.com/metrics/css/animated -->

  <owner>chasej@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Records usage of animated CSS properties used on a page, either statically
    or dynamically, from the time the page is initialised to when it is closed
    or navigated away from. Each property is counted at most once per page per
    view via PageLoadMetricsObserver.

    This histogram counts CSS properties only when they are animated by a CSS
    Animation. Refer to Blink.UseCounter.CSSProperties for more details.

    As of M69, Blink.UseCounter.AnimatedCSSProperties is moved from the blink
    side to the browser side.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.CSSProperties" enum="MappedCSSProperties"
    expires_after="never">
<!-- expires-never: used by Chrome Platform Status dashboard -->

<!-- https://www.chromestatus.com/metrics/css/animated -->

  <owner>chasej@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Records usage of CSS properties used on a page, either statically or
    dynamically, from the time the page is initialised to when it is closed or
    navigated away from. Each property is counted at most once per page per view
    via PageLoadMetricsObserver.

    The first time a CSS property is parsed on a page, the histogram is updated
    to increment the counter. Each histogram bucket corresponds to a CSS
    property (eg. width, border-radius). The exception is the 'Total pages
    measured' bucket - this counts the number of pages that CSS properties were
    counted on. When a page navigation occurs the page count bucket is
    incremented and tracking of the set of which properties have been seen is
    reset.

    These numbers give the percentage of pages that use a CSS property. For
    example, if the 'border-radius' histogram bucket has a count of 250, and the
    page count bucket (i.e. bucket number 1) has a count of 1000 - this means
    that 1000 pages were recorded, and border-radius was used on 25% of those
    pages.

    Note that CSS properties used inside of SVG images are tracked separately in
    the Blink.UseCounter.SVGImage.CSSProperties histogram.

    As of M57 this histogram supercedes WebCore.FeatureObserver.CSSProperties.

    As of M69, Blink.UseCounter.AnimatedCSSProperties is moved from the blink
    side to the browser side.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.DocumentPolicy.Enforced"
    enum="DocumentPolicyFeature" expires_after="2023-03-31">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts enforced DocumentPolicyViolationReport generated in a document.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.DocumentPolicy.Header"
    enum="DocumentPolicyFeature" expires_after="2023-06-04">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the use of a specific document policy via the
    &quot;Document-Policy&quot; HTTP response header.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.DocumentPolicy.PolicyAttribute"
    enum="DocumentPolicyFeature" expires_after="2023-03-31">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the use of a specific document policy via the &quot;policy&quot;
    attribute. Each policy is counted only once per page load.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.DocumentPolicy.ReportOnly"
    enum="DocumentPolicyFeature" expires_after="2023-03-31">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts report only DocumentPolicyViolationReport generated in a document.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.Extensions.Features" enum="FeatureObserver"
    expires_after="never">
<!-- expires-never: While this histogram is not used by the Chrome Platform
     Status dashboard, being able to measure usage of feature in
     chrome-extension:// URLs can still be vitally important when making
     decisions around web platform features, per the documentation at
     https://chromium.googlesource.com/chromium/src/+/HEAD/docs/use_counter_wiki.md#uma-timeline-with-formula. -->

  <owner>chasej@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Count of how many page loads use various features for pages with a
    chrome-extension:// URL only. The PageVisits bucket is incremented for each
    page load, and the other buckets incremented at most once per PageVisit via
    the WebCore::UserCounter class.

    Warning: This histogram represents pre-renderer metrics and so is flawed
    under OOPIF.

    Warning: this histogram was expired from 2021-10-10 to 2022-07-12; data may
    be missing.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FeaturePolicy.Header"
    enum="FeaturePolicyFeature" expires_after="2023-10-22">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the use of a specific feature policy via the
    &quot;Feature-Policy&quot; HTTP response header.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.Features" enum="FeatureObserver"
    expires_after="never">
<!-- expires-never: used by Chrome Platform Status dashboard -->

<!-- https://www.chromestatus.com/metrics/css/animated -->

  <owner>chasej@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Count of how many page loads use various features across all frames in a
    page. The PageVisits bucket is incremented for each page load, and the other
    buckets incremented at most once per PageVisit via blink::UseCounter and
    UseCounterPageLoadMetricsObserver.

    Note that this histogram only counts page with HTTP/HTTPS URL scheme.
    Feature used in pages with other URL schemes might be counted in other
    histograms: &quot;extension://&quot; : Blink.UseCounter.Extensions.Features
    &quot;file://&quot; : Blink.UseCounter.File.Features

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.AnimatedCSSProperties"
    enum="MappedCSSProperties" expires_after="2023-08-30">
  <owner>toyoshim@chromium.org</owner>
  <owner>mparc-dev@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.AnimatedCSSProperties, this records usage of
    animated CSS properties used on a FencedFrame Page. Either statically or
    dynamically, from the time the page is initialised to when it is closed or
    navigated away from. Each property is counted at most once per page per view
    via PageLoadMetricsObserver.

    This histogram counts CSS properties only when they are animated by a CSS
    Animation. Refer to Blink.UseCounter.FencedFrames.CSSProperties for more
    details.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.CSSProperties"
    enum="MappedCSSProperties" expires_after="2023-08-30">
  <owner>toyoshim@chromium.org</owner>
  <owner>mparc-dev@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.CSSProperties, this records usage of CSS
    properties used on a FencedFrame Page. Either statically or dynamically,
    from the time the page is initialised to when it is closed or navigated away
    from. Each property is counted at most once per page per view via
    PageLoadMetricsObserver.

    The first time a CSS property is parsed on a page, the histogram is updated
    to increment the counter. Each histogram bucket corresponds to a CSS
    property (eg. width, border-radius). The exception is the 'Total pages
    measured' bucket - this counts the number of pages that CSS properties were
    counted on. When a page navigation occurs the page count bucket is
    incremented and tracking of the set of which properties have been seen is
    reset.

    These numbers give the percentage of pages that use a CSS property. For
    example, if the 'border-radius' histogram bucket has a count of 250, and the
    page count bucket (i.e. bucket number 1) has a count of 1000 - this means
    that 1000 pages were recorded, and border-radius was used on 25% of those
    pages.

    Note that CSS properties used inside of SVG images are not tracked.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.Features" enum="FeatureObserver"
    expires_after="2023-08-30">
  <owner>toyoshim@chromium.org</owner>
  <owner>mparc-dev@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.Features, this counts how many page loads use
    various features across all frames in a FencedFrame page. The PageVisits
    bucket is incremented for each page load, and the other buckets incremented
    at most once per PageVisit via blink::UseCounter and
    UseCounterPageLoadMetricsObserver.

    Note that this histogram only counts FencedFrames page with HTTP/HTTPS URL
    scheme. Feature used in pages with other URL schemes are not counted.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.MainFrame.Features"
    enum="FeatureObserver" expires_after="2023-08-30">
  <owner>toyoshim@chromium.org</owner>
  <owner>mparc-dev@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.MainFrame.Features, this counts how many page
    loads use various features across in the main frame of a FencedFrame page.
    The PageVisits bucket is incremented at the beginning of each page load and
    the other buckets incremented at most once per PageVisit via
    blink::UseCounter and UseCounterPageLoadMetricsObserver throughout the
    lifetime of a page load metrics observer.

    This histogram counts usage of web features in FencedFrames' main frame
    only. Refer to Blink.UseCounter.FencedFrames.Features for more details.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.PermissionsPolicy.Allow2"
    enum="FeaturePolicyFeature" expires_after="2023-08-01">
  <owner>lbrady@google.com</owner>
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.PermissionsPolicy.Allow2, this counts the use of
    a specific permissions policy feature via the &quot;allow&quot; attribute on
    iframes under FencedFrames root. Each policy is counted only once per page
    load. But the page is limited only to FencedFrames pages.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.FencedFrames.PermissionsPolicy.Header2"
    enum="FeaturePolicyFeature" expires_after="2023-08-01">
  <owner>lbrady@google.com</owner>
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.PermissionsPolicy.Header2, this counts the use
    of a specific permissions policy feature via both &quot;Feature-Policy&quot;
    and &quot;Permissions-Policy&quot; HTTP response header. Each policy is
    counted only once per page load. But the page is limited only to
    FencedFrames pages.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram
    name="Blink.UseCounter.FencedFrames.PermissionsPolicy.Violation.Enforce"
    enum="FeaturePolicyFeature" expires_after="2023-08-01">
  <owner>lbrady@google.com</owner>
  <owner>shivanisha@chromium.org</owner>
  <owner>dom@chromium.org</owner>
  <summary>
    Similar to Blink.UseCounter.PermissionsPolicy.Violation.Enforce, this counts
    the actual enforced permissions policy violation. The metrics is triggered
    when ExecutionContext::IsFeatureEnabled with ReportOptions::ReportOnFailure
    as param returns false, at most once per page visit. But the page is limited
    only to FencedFrames pages.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.File.Features" enum="FeatureObserver"
    expires_after="2024-01-01">
  <owner>yhirano@chromium.org</owner>
  <owner>mkwst@chromium.org</owner>
  <summary>
    Count of how many `file:` URL page loads use various features across all
    frames in the page. This histogram has the same semantics as
    &quot;Blink.UseCounter.Features&quot;, but applies only to `file:` URLs
    (which that histogram does not include).

    Refer to &quot;Blink.UseCounter.Features&quot; for more details.

    This counter expired on 2021-01-28 and was re-enabled on 2022-12-19.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.MainFrame.Features" enum="FeatureObserver"
    expires_after="never">
<!-- expires-never: Companion to Blink.UseCounter.Features, which is also expires-never. -->

  <owner>chasej@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Count of how many page loads use various features across in the main frame
    of a page. The PageVisits bucket is incremented at the beginning of each
    page load and the other buckets incremented at most once per PageVisit via
    blink::UseCounter and UseCounterPageLoadMetricsObserver throughout the
    lifetime of a page load metrics observer.

    This histogram counts usage of web features in main frame only. Refer to
    Blink.UseCounter.Features for more details.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.PermissionsPolicy.Allow2"
    enum="FeaturePolicyFeature" expires_after="2023-10-22">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the use of a specific permissions policy feature via the
    &quot;allow&quot; attribute on iframes. Each policy is counted only once per
    page load. Version 2 fixes the mismatched histogram name with data
    collected.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.PermissionsPolicy.Header2"
    enum="FeaturePolicyFeature" expires_after="2023-11-12">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the use of a specific permissions policy feature via both
    &quot;Feature-Policy&quot; and &quot;Permissions-Policy&quot; HTTP response
    header. Each policy is counted only once per page load. Version 2 fixes the
    mismatched histogram name with data collected.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram name="Blink.UseCounter.PermissionsPolicy.Violation.Enforce"
    enum="FeaturePolicyFeature" expires_after="2023-07-22">
  <owner>iclelland@chromium.org</owner>
  <owner>feature-control@chromium.org</owner>
  <summary>
    Counts the actual enforced permissions policy violation. The metrics is
    triggered when ExecutionContext::IsFeatureEnabled with
    ReportOptions::ReportOnFailure as param returns false, at most once per page
    visit.

    Not recorded if the page is prerendered and cancelled.
  </summary>
</histogram>

<histogram base="true" name="Blink.UserDrivenDocumentUpdate.UpdateTime"
    units="microseconds" expires_after="2023-11-12">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent preparing the document to service user driven behaviors. Examples
    include inspector, selection, editing, find-in-page and focus. Includes time
    spent in style update and layout.

    Note: As of 04/2023, scroll updates are included in user driven behaviors.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.VisibleBeforeLoaded.LazyLoadImages.AboveTheFold2"
    enum="NQEEffectiveConnectionType" expires_after="2023-11-12">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Records the effective connection type whenever a lazily loaded image that
    was initially above the fold becomes visible before it finishes loading.
  </summary>
</histogram>

<histogram name="Blink.VisibleBeforeLoaded.LazyLoadImages.BelowTheFold2"
    enum="NQEEffectiveConnectionType" expires_after="2023-11-05">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Records the effective connection type whenever a lazily loaded image that
    was initially below the fold becomes visible before it finishes loading.
  </summary>
</histogram>

<histogram name="Blink.VisibleLoadTime.LazyLoadImages" units="ms"
    expires_after="2023-09-01">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Milliseconds spent waiting for a lazily loaded image to load. 0ms is
    recorded if the image is already loaded by the time it is visible.

    See also the AboveTheFold3 and BelowTheFold3 versions of this metric.
  </summary>
</histogram>

<histogram
    name="Blink.VisibleLoadTime.LazyLoadImages.AboveTheFold3{BlinkVisibleLoadTimeSuffixes}"
    units="ms" expires_after="2023-09-01">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Milliseconds spent waiting for an initially above-the-fold lazily loaded
    image to load. 0ms is recorded if the image is already loaded by the time it
    is visible. EffectiveConnectionType (2G, 3G, etc) is recorded as suffix to
    this histogram. View the base histogram to see results aggregated across all
    connection types. {BlinkVisibleLoadTimeSuffixes}
  </summary>
  <token key="BlinkVisibleLoadTimeSuffixes"
      variants="BlinkVisibleLoadTimeSuffixes"/>
</histogram>

<histogram
    name="Blink.VisibleLoadTime.LazyLoadImages.BelowTheFold3{BlinkVisibleLoadTimeSuffixes}"
    units="ms" expires_after="2023-09-01">
  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Milliseconds spent waiting for an initially below-the-fold lazily loaded
    image to load. 0ms is recorded if the image is already loaded by the it is
    visible. EffectiveConnectionType (2G, 3G, etc) is recorded as suffix to this
    histogram. View the base histogram to see results aggregated across all
    connection types. {BlinkVisibleLoadTimeSuffixes}
  </summary>
  <token key="BlinkVisibleLoadTimeSuffixes"
      variants="BlinkVisibleLoadTimeSuffixes"/>
</histogram>

<histogram base="true" name="Blink.VisualUpdateDelay.UpdateTime"
    units="microseconds" expires_after="2023-11-12">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>szager@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Elapsed time between when a widget first registers a state invalidation that
    requires a visual refresh; and when the main thread begins a main frame that
    will send the updated visual state to the compositor.

    This histogram only records metrics on machines with high-resolution clocks.
  </summary>
</histogram>

<histogram base="true" name="Blink.WaitForCommit.UpdateTime"
    units="microseconds" expires_after="2023-10-08">
<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePreFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimePostFCPSuffixes" -->

<!-- Name completed by histogram_suffixes name="BlinkUpdateTimeAggregatedSuffixes" -->

  <owner>pdr@chromium.org</owner>
  <owner>paint-dev@chromium.org</owner>
  <summary>
    Time spent waiting for the compositor thread to begin processing a layer
    update inside ProxyMain::BeginMainFrame.

    Note: PreFCP metrics will be recorded even if FCP is not reached, whereas
    AggregatedPreFCP metrics are only recorded if FCP is reached.

    Note: Not recorded on ~5% of Windows machines with low-resolution clocks.

    Note: The histograms with PreFCP/PostFCP/AggregatedPreFCP suffixes before
    105.0.5175.0 were impacted by https://crbug.com/1330675. Be careful when
    aggregating or comparing these histograms across the version.
  </summary>
</histogram>

<histogram name="Blink.WebCodecs.ImageDecoder.Success" enum="BooleanSuccess"
    expires_after="never">
<!-- expires-never: WebCodecs health metric. -->

  <owner>dalecurtis@chromium.org</owner>
  <owner>media-dev@chromium.org</owner>
  <summary>
    Whether a given JavaScript ImageDecoder instance completed operation
    successfully or not. Logged upon destruction of the instance.
  </summary>
</histogram>

<histogram name="Blink.WebCodecs.ImageDecoder.Type" enum="DecodedImageType"
    expires_after="never">
<!-- expires-never: WebCodecs health metric. -->

  <owner>dalecurtis@chromium.org</owner>
  <owner>media-dev@chromium.org</owner>
  <summary>
    Image codec provided to JavaScript ImageDecoder constructor. Logged once per
    successful construction upon completion of construction.
  </summary>
</histogram>

<histogram name="Blink.WebCodecs.{AudioCodecApi}.Codec" enum="AudioCodec"
    expires_after="never">
<!-- expires-never: WebCodecs health metric. -->

  <owner>dalecurtis@chromium.org</owner>
  <owner>media-dev@chromium.org</owner>
  <summary>
    The codec type used with {AudioCodecApi}. Recorded for every successful
    configure() call.
  </summary>
  <token key="AudioCodecApi">
    <variant name="AudioDecoder"/>
    <variant name="AudioEncoder"/>
  </token>
</histogram>

<histogram name="Blink.WebCodecs.{CodecApi}.FinalStatus" enum="MediaStatusCode"
    expires_after="never">
<!-- expires-never: WebCodecs health metric. -->

  <owner>dalecurtis@chromium.org</owner>
  <owner>media-dev@chromium.org</owner>
  <summary>
    The final media::StatusCode for each {CodecApi} instance. The final status
    code is either StatusCode::kOk or the first fatal error encountered.
    Recorded once upon destruction for each codec type.
  </summary>
  <token key="CodecApi">
    <variant name="AudioDecoder"/>
    <variant name="AudioEncoder"/>
    <variant name="VideoDecoder"/>
    <variant name="VideoEncoder"/>
  </token>
</histogram>

<histogram name="Blink.WebCodecs.{VideoCodecApi}.Codec" enum="VideoCodec"
    expires_after="never">
<!-- expires-never: WebCodecs health metric. -->

  <owner>dalecurtis@chromium.org</owner>
  <owner>media-dev@chromium.org</owner>
  <summary>
    The codec type used with {VideoCodecApi}. Recorded for every successful
    configure() call.
  </summary>
  <token key="VideoCodecApi">
    <variant name="VideoDecoder"/>
    <variant name="VideoEncoder"/>
  </token>
</histogram>

<histogram name="Blink.{CookieOperation}Time.Manager{ManagerState}" units="ms"
    expires_after="2023-08-09">
  <owner>cduvall@chromium.org</owner>
  <owner>jam@chromium.org</owner>
  <summary>
    Measures the time it takes to perform a {CookieOperation} operation from the
    CookieJar when the CookieManager is {ManagerState}. Logged on every
    operation from the CookieJar.
  </summary>
  <token key="CookieOperation">
    <variant name="Cookies"/>
    <variant name="CookiesEnabled"/>
    <variant name="SetCookie"/>
  </token>
  <token key="ManagerState">
    <variant name="Available"/>
    <variant name="Requested"/>
  </token>
</histogram>

<histogram name="Blink.{Host}.RenderTaskDuration.{Context}.{Filter}"
    units="microseconds" expires_after="2024-04-01">
  <owner>junov@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Time spent executing a script task that draws content to a {Context} context
    of a {Host}.

    Note: This metric drops reports on clients with low-resolution clocks, which
    means these reports will be biased against a portion of the population on
    Windows. See Windows.HasHighResolutionTimeTicks for the affected sample.
  </summary>
  <token key="Host">
    <variant name="Canvas"/>
    <variant name="OffscreenCanvas"/>
  </token>
  <token key="Context">
    <variant name="2D.Accelerated"/>
    <variant name="2D.Unaccelerated"/>
    <variant name="ImageBitmap"/>
    <variant name="WebGL"/>
    <variant name="WebGL2"/>
    <variant name="WebGPU"/>
  </token>
  <token key="Filter">
    <variant name="All"/>
    <variant name="Animation"/>
    <variant name="DrawArrays"/>
    <variant name="DrawElements"/>
    <variant name="Image"/>
    <variant name="ImageData"/>
    <variant name="Path"/>
    <variant name="Rectangle"/>
    <variant name="Text"/>
  </token>
</histogram>

<histogram name="Blink.{Host}.{Heap}.{Context}" units="KB"
    expires_after="2024-04-01">
  <owner>junov@chromium.org</owner>
  <owner>fserb@chromium.org</owner>
  <owner>aaronhk@chromium.org</owner>
  <summary>
    Memory usage on the {Heap} heap in KB, sampled after the execution of script
    tasks that render content to a {Host}, using a {Context} context.
  </summary>
  <token key="Host">
    <variant name="Canvas"/>
    <variant name="OffscreenCanvas"/>
  </token>
  <token key="Heap">
    <variant name="BlinkGC"/>
    <variant name="PartitionAlloc"/>
  </token>
  <token key="Context">
    <variant name="2D.Accelerated"/>
    <variant name="2D.Unaccelerated"/>
    <variant name="ImageBitmap"/>
    <variant name="WebGL"/>
    <variant name="WebGL2"/>
    <variant name="WebGPU"/>
  </token>
</histogram>

</histograms>

</histogram-configuration>