Bug 1072639 - Fix context for web app notifications. r=snorp

mobile/android/base/NotificationHelper.java

@@ -195,6 +195,7 @@ public final class NotificationHelper implements GeckoEventListener {
         notificationIntent.setData(dataUri);
         notificationIntent.putExtra(HELPER_NOTIFICATION, true);
         notificationIntent.putExtra(COOKIE_ATTR, message.optString(COOKIE_ATTR));
+        notificationIntent.setClass(mContext, GeckoAppShell.getGeckoInterface().getActivity().getClass());
         return notificationIntent;
     }