Add brokenSiteReport metric

Author: sammacbeth

shared/js/background/background.js

@@ -32,7 +32,7 @@ import RemoteConfig from './components/remote-config';
 import initDebugBuild from './devbuild';
 import initReloader from './devbuild-reloader';
 import tabManager from './tab-manager';
-import AbnExperimentMetrics, { AppUseMetric, SearchMetric } from './components/abn-experiments';
+import AbnExperimentMetrics, { AppUseMetric, PixelMetric, SearchMetric } from './components/abn-experiments';
 // NOTE: this needs to be the first thing that's require()d when the extension loads.
 // otherwise FF might miss the onInstalled event
 require('./events');
@@ -78,7 +78,7 @@ const components = {
 if (BUILD_TARGET === 'chrome' || BUILD_TARGET === 'chrome-mv2') {
     const abnMetrics = new AbnExperimentMetrics({ remoteConfig });
     components.abnMetrics = abnMetrics;
-    components.metrics = [new AppUseMetric({ abnMetrics }), new SearchMetric({ abnMetrics })];
+    components.metrics = [new AppUseMetric({ abnMetrics }), new SearchMetric({ abnMetrics }), new PixelMetric({ abnMetrics })];
     components.fireButton = new FireButton({ settings, tabManager });
 }
 // MV3-only components

shared/js/background/components/abn-experiments.js

@@ -84,6 +84,32 @@ export class SearchMetric {
     }
 }
 
+export class PixelMetric {
+    /**
+     * Metric that observes outgoing pixel calls and routes a subset of them as experiment metrics.
+     * Currently intercepts `epbf` pixels and triggers a `brokenSiteReport` metric.
+     * @param {{
+     * abnMetrics: AbnExperimentMetrics
+    * }} opts
+     */
+    constructor({ abnMetrics }) {
+        browser.webRequest.onCompleted.addListener(
+            async (details) => {
+                await abnMetrics.remoteConfig.ready;
+                const url = new URL(details.url);
+                if (url.pathname.startsWith('/t/epbf_')) {
+                    // broken site report
+                    abnMetrics.onMetricTriggered('brokenSiteReport');
+                }
+            },
+            {
+                urls: ['https://improving.duckduckgo.com/t/*'],
+                tabId: -1,
+            },
+        );
+    }
+}
+
 export default class AbnExperimentMetrics {
     /**
      *
@@ -123,7 +149,6 @@ export default class AbnExperimentMetrics {
      * @param {number} [timestamp]
      */
     async onMetricTriggered(metric, value = 1, timestamp) {
-        console.log('xxx metric triggered:', metric);
         this.remoteConfig
             .getSubFeatureStatuses()
             .filter((status) => status.hasCohorts && status.cohort && status.cohort.enrolledAt)