Bug 1330954 - fix leakiness of SHIELD system add-on and re-enable test, r=kmag,mythmon

There are 3 issues this tackles:
- we were keeping a reference to the notification we added (this.notice),
  which kept windows alive.
- we had the CleanupManager keep a reference to our close method, which kept
  a reference to us, which kept a reference to the window.
- the fact that we use timeouts to call this.close() in 2 places meant
  this.close would get called multiple times, which meant we errored out on
  later occasions, because various things had been nulled out. This tidies up
  the timeouts when cleanup is called to avoid re-entrancy/errors/leaks.

MozReview-Commit-ID: EYvK7bQEh3X

--HG--
extra : rebase_source : 8646b7fe965b7110a69a728b54e5c149c750f9c3

browser/extensions/shield-recipe-client/lib/CleanupManager.jsm

@@ -6,16 +6,24 @@
 
 this.EXPORTED_SYMBOLS = ["CleanupManager"];
 
-const cleanupHandlers = [];
+const cleanupHandlers = new Set();
 
 this.CleanupManager = {
   addCleanupHandler(handler) {
-    cleanupHandlers.push(handler);
+    cleanupHandlers.add(handler);
+  },
+
+  removeCleanupHandler(handler) {
+    cleanupHandlers.delete(handler);
   },
 
   cleanup() {
     for (const handler of cleanupHandlers) {
-      handler();
+      try {
+        handler();
+      } catch (ex) {
+        Cu.reportError(ex);
+      }
     }
   },
 };

browser/extensions/shield-recipe-client/lib/Heartbeat.jsm

@@ -100,6 +100,7 @@ this.Heartbeat = class {
 
     // so event handlers are consistent
     this.handleWindowClosed = this.handleWindowClosed.bind(this);
+    this.close = this.close.bind(this);
 
     if (this.options.engagementButtonLabel) {
       this.buttons = [{
@@ -208,7 +209,7 @@ this.Heartbeat = class {
     }, surveyDuration);
 
     this.sandboxManager.addHold("heartbeat");
-    CleanupManager.addCleanupHandler(() => this.close());
+    CleanupManager.addCleanupHandler(this.close);
   }
 
   maybeNotifyHeartbeat(name, data = {}) {
@@ -281,10 +282,7 @@ this.Heartbeat = class {
       this.eventEmitter.emit("TelemetrySent", Cu.cloneInto(payload, this.sandboxManager.sandbox));
 
       // Survey is complete, clear out the expiry timer & survey configuration
-      if (this.surveyEndTimer) {
-        clearTimeout(this.surveyEndTimer);
-        this.surveyEndTimer = null;
-      }
+      this.endTimerIfPresent("surveyEndTimer");
 
       this.pingSent = true;
       this.surveyResults = null;
@@ -315,12 +313,16 @@ this.Heartbeat = class {
       this.chromeWindow.gBrowser.selectedTab = this.chromeWindow.gBrowser.addTab(this.options.postAnswerUrl.toString());
     }
 
-    if (this.surveyEndTimer) {
-      clearTimeout(this.surveyEndTimer);
-      this.surveyEndTimer = null;
-    }
+    this.endTimerIfPresent("surveyEndTimer");
 
-    setTimeout(() => this.close(), NOTIFICATION_TIME);
+    this.engagementCloseTimer = setTimeout(() => this.close(), NOTIFICATION_TIME);
+  }
+
+  endTimerIfPresent(timerName) {
+    if (this[timerName]) {
+      clearTimeout(this[timerName]);
+      this[timerName] = null;
+    }
   }
 
   handleWindowClosed() {
@@ -333,6 +335,10 @@ this.Heartbeat = class {
   }
 
   cleanup() {
+    // Kill the timers which might call things after we've cleaned up:
+    this.endTimerIfPresent("surveyEndTimer");
+    this.endTimerIfPresent("engagementCloseTimer");
+
     this.sandboxManager.removeHold("heartbeat");
     // remove listeners
     this.chromeWindow.removeEventListener("SSWindowClosing", this.handleWindowClosed);
@@ -340,7 +346,10 @@ this.Heartbeat = class {
     this.chromeWindow = null;
     this.notificationBox = null;
     this.notification = null;
+    this.notice = null;
     this.eventEmitter = null;
     this.sandboxManager = null;
+    // Ensure we don't re-enter and release the CleanupManager's reference to us:
+    CleanupManager.removeCleanupHandler(this.close);
   }
 };

browser/extensions/shield-recipe-client/test/browser.ini

@@ -3,7 +3,6 @@
 [browser_EventEmitter.js]
 [browser_Storage.js]
 [browser_Heartbeat.js]
-skip-if = true # bug 1325409
 [browser_NormandyApi.js]
   support-files =
     test_server.sjs