Add metrics for Blob URL usage in data URL workers

Note that I didn't see an easy way to add tests for this,
but I verified that the histograms were updated after running
the following WPT that creates a Blob URL from a data URL
worker:

html/infrastructure/safe-passing-of-structured-data/shared-array-buffers/blob-data.https.html

(cherry picked from commit 2d7cca1)

Bug: 1058759,1325852
Change-Id: I9644d69fb143b89ff6cd512a3758aba5b15e3b27
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3639563
Commit-Queue: Andrew Williams <awillia@google.com>
Reviewed-by: Ayu Ishii <ayui@chromium.org>
Cr-Original-Commit-Position: refs/heads/main@{#1002966}
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3649946
Cr-Commit-Position: refs/branch-heads/5060@{#33}
Cr-Branched-From: b83393d-refs/heads/main@{#1002911}

third_party/blink/renderer/core/fileapi/public_url_manager.cc

@@ -26,6 +26,7 @@
 
 #include "third_party/blink/renderer/core/fileapi/public_url_manager.h"
 
+#include "base/metrics/histogram_functions.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/unguessable_token.h"
 #include "mojo/public/cpp/bindings/pending_remote.h"
@@ -35,6 +36,7 @@
 #include "third_party/blink/renderer/core/execution_context/execution_context.h"
 #include "third_party/blink/renderer/core/fileapi/url_registry.h"
 #include "third_party/blink/renderer/core/frame/local_dom_window.h"
+#include "third_party/blink/renderer/core/workers/worker_global_scope.h"
 #include "third_party/blink/renderer/platform/blob/blob_data.h"
 #include "third_party/blink/renderer/platform/blob/blob_url.h"
 #include "third_party/blink/renderer/platform/blob/blob_url_null_origin_map.h"
@@ -76,6 +78,19 @@ String PublicURLManager::RegisterURL(URLRegistrable* registrable) {
   DCHECK(!url.IsEmpty());
   const String& url_string = url.GetString();
 
+  // Collect metrics on how frequently a worker context that makes use of the
+  // Blob URL API was created from a data URL. Note that we ignore service
+  // workers for this since they can't be created from data URLs.
+  if (GetExecutionContext()->IsWorkerGlobalScope()) {
+    WorkerGlobalScope* worker_global_scope =
+        DynamicTo<WorkerGlobalScope>(GetExecutionContext());
+    if (worker_global_scope->IsDedicatedWorkerGlobalScope() ||
+        worker_global_scope->IsSharedWorkerGlobalScope()) {
+      base::UmaHistogramBoolean("Storage.Blob.DataURLWorkerRegister",
+                                worker_global_scope->Url().ProtocolIsData());
+    }
+  }
+
   if (registrable->IsMojoBlob()) {
     // Measure how much jank the following synchronous IPC introduces.
     SCOPED_UMA_HISTOGRAM_TIMER("Storage.Blob.RegisterPublicURLTime");
@@ -143,6 +158,25 @@ void PublicURLManager::Resolve(
     return;
 
   DCHECK(url.ProtocolIs("blob"));
+
+  // Collect metrics on how frequently a worker context that makes use of the
+  // Blob URL API was created from a data URL. Note that we ignore service
+  // workers for this since they can't be created from data URLs.
+  if (GetExecutionContext()->IsWorkerGlobalScope()) {
+    WorkerGlobalScope* worker_global_scope =
+        DynamicTo<WorkerGlobalScope>(GetExecutionContext());
+    // Note that for module workers created from blob URLs, this gets called
+    // before the worker global scope has been initialized. Thus, no valid URL
+    // is available.
+    if (worker_global_scope->IsUrlValid() &&
+        (worker_global_scope->IsDedicatedWorkerGlobalScope() ||
+         worker_global_scope->IsSharedWorkerGlobalScope())) {
+      base::UmaHistogramBoolean(
+          "Storage.Blob.DataURLWorkerResolveAsURLLoaderFactory",
+          worker_global_scope->Url().ProtocolIsData());
+    }
+  }
+
   url_store_->ResolveAsURLLoaderFactory(
       url, std::move(factory_receiver),
       WTF::Bind(
@@ -198,6 +232,24 @@ void PublicURLManager::Resolve(
     return;
 
   DCHECK(url.ProtocolIs("blob"));
+
+  // Collect metrics on how frequently a worker context that makes use of the
+  // Blob URL API was created from a data URL. Note that we ignore service
+  // workers for this since they can't be created from data URLs.
+  if (GetExecutionContext()->IsWorkerGlobalScope()) {
+    WorkerGlobalScope* worker_global_scope =
+        DynamicTo<WorkerGlobalScope>(GetExecutionContext());
+    // Note that the URL validity check here is not known to be needed but
+    // adding it just in case!
+    if (worker_global_scope->IsUrlValid() &&
+        (worker_global_scope->IsDedicatedWorkerGlobalScope() ||
+         worker_global_scope->IsSharedWorkerGlobalScope())) {
+      base::UmaHistogramBoolean(
+          "Storage.Blob.DataURLWorkerResolveForNavigation",
+          worker_global_scope->Url().ProtocolIsData());
+    }
+  }
+
   url_store_->ResolveForNavigation(
       url, std::move(token_receiver),
       WTF::Bind(

tools/metrics/histograms/metadata/storage/histograms.xml

@@ -256,6 +256,39 @@ chromium-metrics-reviews@google.com.
   </summary>
 </histogram>
 
+<histogram name="Storage.Blob.DataURLWorkerRegister" enum="Boolean"
+    expires_after="M106">
+  <owner>awillia@chromium.org</owner>
+  <owner>ayui@chromium.org</owner>
+  <summary>
+    Recorded when the PublicURLManager::Register method is called from a worker
+    execution context (excluding service worker contexts). The value indicates
+    if the worker was created from a data URL.
+  </summary>
+</histogram>
+
+<histogram name="Storage.Blob.DataURLWorkerResolveAsURLLoaderFactory"
+    enum="Boolean" expires_after="M106">
+  <owner>awillia@chromium.org</owner>
+  <owner>ayui@chromium.org</owner>
+  <summary>
+    Recorded when the PublicURLManager::Resolve URLLoaderFactory method is
+    called from a worker execution context (excluding service worker contexts).
+    The value indicates if the worker was created from a data URL.
+  </summary>
+</histogram>
+
+<histogram name="Storage.Blob.DataURLWorkerResolveForNavigation" enum="Boolean"
+    expires_after="M106">
+  <owner>awillia@chromium.org</owner>
+  <owner>ayui@chromium.org</owner>
+  <summary>
+    Recorded when the PublicURLManager::Resolve method for navigations is called
+    from a worker execution context (excluding service worker contexts). The
+    value indicates if the worker was created from a data URL.
+  </summary>
+</histogram>
+
 <histogram name="Storage.Blob.FileReaderLoader.FailureType"
     enum="FileReaderLoaderFailureType" expires_after="M95">
   <owner>mek@chromium.org</owner>