Bug 612551 - Clear appshell observers on xpcom-shutdown. r=blassey a=blocking-fennec

widget/src/android/nsAppShell.cpp

@@ -75,6 +75,8 @@ nsIGeolocationUpdate *gLocationCallback = nsnull;
 
 nsAppShell *nsAppShell::gAppShell = nsnull;
 
+NS_IMPL_ISUPPORTS_INHERITED1(nsAppShell, nsBaseAppShell, nsIObserver)
+
 nsAppShell::nsAppShell()
     : mQueueLock(nsnull),
       mCondLock(nsnull),
@@ -114,9 +116,27 @@ nsAppShell::Init()
     nsresult rv = nsBaseAppShell::Init();
     if (AndroidBridge::Bridge())
         AndroidBridge::Bridge()->NotifyAppShellReady();
+
+    nsCOMPtr<nsIObserverService> obsServ =
+            mozilla::services::GetObserverService();
+    if (obsServ) {
+        obsServ->AddObserver(this, "xpcom-shutdown", PR_FALSE);
+    }
     return rv;
 }
 
+NS_IMETHODIMP
+nsAppShell::Observe(nsISupports* aSubject,
+                    const char* aTopic,
+                    const PRUnichar* aData)
+{
+    if (!strcmp(aTopic, "xpcom-shutdown")) {
+        // We need to ensure no observers stick around after XPCOM shuts down
+        // or we'll see crashes, as the app shell outlives XPConnect.
+        mObserversHash.Clear();
+    }
+    return nsBaseAppShell::Observe(aSubject, aTopic, aData);
+}
 
 void
 nsAppShell::ScheduleNativeEventCallback()

widget/src/android/nsAppShell.h

@@ -61,6 +61,9 @@ public:
 
     nsAppShell();
 
+    NS_DECL_ISUPPORTS_INHERITED
+    NS_DECL_NSIOBSERVER
+
     nsresult Init();
 
     void NotifyNativeEvent();