Revert smart unblock threshold to 30 seconds. Add comments explaining…

… that the difference for thresholds for metrics and smart block is intentional.

src/classes/Metrics.js

@@ -30,7 +30,12 @@ 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
+
+// Note that this threshold is intentionally different from the 30 second threshold in PolicySmartBlock,
+// which is used to set the reloaded property on tab objects and to activate smart unblock behavior
+// see GH-1797 for more details
+const BROKEN_PAGE_METRICS_THRESHOLD = 60000; // 60 seconds
+
 /**
  * Class for handling telemetry pings.
  * @memberOf  BackgroundClasses
@@ -156,7 +161,7 @@ class Metrics {
 				on: true,
 				triggerId,
 				triggerTime: Date.now(),
-				timeoutId: setTimeout(this._clearBrokenPageWatcher, BROKEN_PAGE_WATCH_THRESHOLD),
+				timeoutId: setTimeout(this._clearBrokenPageWatcher, BROKEN_PAGE_METRICS_THRESHOLD),
 				url: tabUrl,
 			});
 		});

src/classes/PolicySmartBlock.js

@@ -251,11 +251,13 @@ class PolicySmartBlock {
 	checkReloadThreshold(tabId) {
 		if (!this.shouldCheck(tabId)) { return false; }
 
-		const THRESHHOLD = 60000; // 60 seconds
+		// Note that this threshold is different from the broken page ping threshold in Metrics, which is 60 seconds
+		// see GH-1797 for more details
+		const SMART_BLOCK_BEHAVIOR_THRESHOLD = 30000; // 30 seconds
 
 		return (
 			tabInfo.getTabInfoPersist(tabId, 'numOfReloads') > 1 &&
-			((Date.now() - tabInfo.getTabInfoPersist(tabId, 'firstLoadTimestamp')) < THRESHHOLD) || false
+			((Date.now() - tabInfo.getTabInfoPersist(tabId, 'firstLoadTimestamp')) < SMART_BLOCK_BEHAVIOR_THRESHOLD) || false
 		);
 	}
 

src/classes/TabInfo.js

@@ -69,7 +69,7 @@ class TabInfo {
 			},
 			insecureRedirects: [],
 		};
-		
+
 		this._tabInfo[tab_id] = info;
 		this._updateUrl(tab_id, tab_url);
 	}