Add startPossibleBrokenPageTimer method to Metrics, implement the del…

…ayed off switch for the watcher, and set it to trigger on site whitelist

src/background.js

@@ -1101,6 +1101,7 @@ function initializeDispatcher() {
 		button.update();
 		utils.flushChromeMemoryCache();
 		cliqz.modules.core.action('refreshAppState');
+		metrics.startPossibleBrokenPageTimer();
 	});
 	dispatcher.on('conf.save.enable_human_web', (enableHumanWeb) => {
 		if (!IS_CLIQZ) {

src/classes/Metrics.js

@@ -30,6 +30,7 @@ const FIRST_REWARD_METRICS = ['rewards_first_accept', 'rewards_first_reject', 'r
 const { METRICS_SUB_DOMAIN, EXTENSION_VERSION, BROWSER_INFO } = globals;
 const IS_EDGE = (BROWSER_INFO.name === 'edge');
 const MAX_DELAYED_PINGS = 100;
+const BROKEN_PAGE_WATCH_THRESHOLD = 60000; // 60 seconds
 /**
  * Class for handling telemetry pings.
  * @memberOf  BackgroundClasses
@@ -39,6 +40,9 @@ class Metrics {
 		this.utm_source = '';
 		this.utm_campaign = '';
 		this.ping_set = new Set();
+		this._pageMightBeBroken = false;
+		this._pageMightBeBrokenOffSwitch = null;
+		this._brokenPageOnNewTabListener = null;
 	}
 
 	/**
@@ -107,6 +111,21 @@ class Metrics {
 			});
 	}
 
+	startPossibleBrokenPageTimer() {
+		this._pageMightBeBroken = true;
+
+		// Stand down after a minute
+		if (this._pageMightBeBrokenOffSwitch) {
+			clearTimeout(this._pageMightBeBrokenOffSwitch);
+		}
+		this._pageMightBeBrokenOffSwitch = setTimeout(() => {
+			this._pageMightBeBroken = false;
+			},
+			BROKEN_PAGE_WATCH_THRESHOLD
+		);
+
+	}
+
 	/**
 	* Prepare data and send telemetry pings.
 	* @param {string} type    type of the telemetry ping