Make Notification override hasPendingActivity() to prolong its lifetime while async op is running

Source/platform/AsyncMethodRunner.h

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 92 matching lines @@
             m_runWhenResumed = false;
             m_suspended = false;
             return;
         }
 
         ASSERT(!m_runWhenResumed);
         if (m_timer.isActive())
             m_timer.stop();
     }
 
+    bool isActive() const
+    {
+        return m_timer.isActive();
+    }
+
 private:
     void fired(Timer<AsyncMethodRunner<TargetClass> >*) { (m_object->*m_method)(); }
 
     Timer<AsyncMethodRunner<TargetClass> > m_timer;
 
     TargetClass* m_object;
     TargetMethod m_method;
 
     bool m_suspended;
     bool m_runWhenResumed;
 };
 
 }
 
 #endif