Never (re)start NavigatorGamepad platform event updating once detached.

Source/modules/gamepad/NavigatorGamepad.h

 /*
  * Copyright (C) 2011, 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:
  *
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 44 matching lines @@
 
     void didConnectOrDisconnectGamepad(unsigned index, const WebGamepad&, bool connected);
 
 private:
     explicit NavigatorGamepad(LocalFrame*);
 
     static const char* supplementName();
 
     void dispatchOneEvent();
     void didRemoveGamepadEventListeners();
+    bool startUpdatingIfAttached();
 
     // DOMWindowProperty
     virtual void willDestroyGlobalObjectInFrame() override;
     virtual void willDetachGlobalObjectFromFrame() override;
 
     // PlatformEventController
     virtual void registerWithDispatcher() override;
     virtual void unregisterWithDispatcher() override;
     virtual bool hasLastData() override;
     virtual void didUpdateData() override;
     virtual void pageVisibilityChanged() override;
 
     // DOMWindowLifecycleObserver
     virtual void didAddEventListener(LocalDOMWindow*, const AtomicString&) override;
     virtual void didRemoveEventListener(LocalDOMWindow*, const AtomicString&) override;
     virtual void didRemoveAllEventListeners(LocalDOMWindow*) override;
 
     PersistentWillBeMember<GamepadList> m_gamepads;
     PersistentHeapDequeWillBeHeapDeque<Member<Gamepad>> m_pendingEvents;
     AsyncMethodRunner<NavigatorGamepad> m_dispatchOneEventRunner;
 };
 
 } // namespace blink
 
 #endif // NavigatorGamepad_h