report: add onViewTrace to renderer options

lighthouse-core/test/results/sample_v2.json

@@ -8729,6 +8729,8 @@
       "throttlingProvided": "Provided by environment",
       "toplevelWarningsMessage": "There were issues affecting this run of Lighthouse:",
       "varianceDisclaimer": "Values are estimated and may vary. The [performance score is calculated](https://web.dev/performance-scoring/) directly from these metrics.",
+      "viewOriginalTraceLabel": "View Original Trace",
+      "viewTraceLabel": "View Trace",
       "viewTreemapLabel": "View Treemap",
       "warningAuditsGroupTitle": "Passed audits but with warnings",
       "warningHeader": "Warnings: "

lighthouse-core/util-commonjs.js

@@ -630,6 +630,10 @@ const UIStrings = {
   thirdPartyResourcesLabel: 'Show 3rd-party resources',
   /** This label is for a button that opens a new tab to a webapp called "Treemap", which is a nested visual representation of a heierarchy of data related to the reports (script bytes and coverage, resource breakdown, etc.) */
   viewTreemapLabel: 'View Treemap',
+  /** This label is for a button that will show the user a trace of the page. */
+  viewTraceLabel: 'View Trace',
+  /** This label is for a button that will show the user a trace of the page. */
+  viewOriginalTraceLabel: 'View Original Trace',
 
   /** Option in a dropdown menu that opens a small, summary report in a print dialog.  */
   dropdownPrintSummary: 'Print Summary',

proto/lighthouse-result.proto

@@ -567,6 +567,12 @@ message I18n {
 
     // Label indicating that Lighthouse throttled the page using custom throttling settings.
     string runtime_custom = 57;
+
+    // This label is for a button that will show the user a trace of the page.
+    string view_trace_label = 58;
+
+    // This label is for a button that will show the user a trace of the page.
+    string view_original_trace_label = 59;
   }
 
   // The message holding all formatted strings used in the renderer.

report/renderer/report-ui-features.js

@@ -112,6 +112,15 @@ export class ReportUIFeatures {
       });
     }
 
+    if (this._opts.onViewTrace) {
+      this.addButton({
+        text: lhr.configSettings.throttlingMethod === 'simulate' ?
+          Util.i18n.strings.viewOriginalTraceLabel :
+          Util.i18n.strings.viewTraceLabel,
+        onClick: () => this._opts.onViewTrace?.(),
+      });
+    }
+
     if (this._opts.getStandaloneReportHTML) {
       this._dom.find('a[data-action="save-html"]', this._dom.rootEl).classList.remove('lh-hidden');
     }

report/renderer/util.js

@@ -627,6 +627,10 @@ const UIStrings = {
   thirdPartyResourcesLabel: 'Show 3rd-party resources',
   /** This label is for a button that opens a new tab to a webapp called "Treemap", which is a nested visual representation of a heierarchy of data related to the reports (script bytes and coverage, resource breakdown, etc.) */
   viewTreemapLabel: 'View Treemap',
+  /** This label is for a button that will show the user a trace of the page. */
+  viewTraceLabel: 'View Trace',
+  /** This label is for a button that will show the user a trace of the page. */
+  viewOriginalTraceLabel: 'View Original Trace',
 
   /** Option in a dropdown menu that opens a small, summary report in a print dialog.  */
   dropdownPrintSummary: 'Print Summary',

report/types/report-renderer.d.ts

@@ -5,6 +5,7 @@
  */
 
 import { Result as AuditResult } from "../../types/lhr/audit-result";
+import { ReportUIFeatures } from "../renderer/report-ui-features.js";
 
 declare module Renderer {
   function renderReport(lhr: AuditResult, options?: Options): HTMLElement;
@@ -26,6 +27,12 @@ declare module Renderer {
     onPageAnchorRendered?: (link: HTMLAnchorElement) => void;
     /** If defined, `Save as HTML` option is shown in dropdown menu. */
     getStandaloneReportHTML?: () => string;
+    /**
+     * If defined, adds a `View Trace` button to the report, and calls this callback when clicked.
+     * The callback should do something to present the user with a visualization of the trace
+     * data, which can be gotten from the artifacts.
+     */
+    onViewTrace?: () => void;
   }
 }