Implement WebVR presentation pausing for VR Shell Menu Mode

device/vr/android/gvr/gvr_gamepad_data_fetcher.h

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef DEVICE_VR_ANDROID_GVR_GAMEPAD_DATA_FETCHER_H_
 #define DEVICE_VR_ANDROID_GVR_GAMEPAD_DATA_FETCHER_H_
 
 #include <string>
 
+#include "base/memory/weak_ptr.h"
 #include "device/gamepad/gamepad_data_fetcher.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr_controller.h"
 #include "third_party/gvr-android-sdk/src/ndk/include/vr/gvr/capi/include/gvr_types.h"
 
 namespace device {
 
 class GvrDelegate;
 
 class GvrGamepadDataFetcher : public GamepadDataFetcher {
  public:
   class Factory : public GamepadDataFetcherFactory {
    public:
-    Factory(GvrDelegate* delegate, unsigned int display_id);
+    Factory(const base::WeakPtr<GvrDelegate>& delegate,
+            unsigned int display_id);
     ~Factory() override;
     std::unique_ptr<GamepadDataFetcher> CreateDataFetcher() override;
     GamepadSource source() override;
 
    private:
-    GvrDelegate* delegate_;
+    base::WeakPtr<GvrDelegate> delegate_;
     unsigned int display_id_;
   };
 
   GvrGamepadDataFetcher(GvrDelegate* delegate, unsigned int display_id);
   ~GvrGamepadDataFetcher() override;
 
   GamepadSource source() override;
 
   void GetGamepadData(bool devices_changed_hint) override;
   void PauseHint(bool paused) override;
   void OnAddedToProvider() override;
 
  private:
   std::unique_ptr<gvr::ControllerApi> controller_api_;
   std::unique_ptr<gvr::UserPrefs> user_prefs_;
   gvr::ControllerState controller_state_;
   unsigned int display_id_;
 
   DISALLOW_COPY_AND_ASSIGN(GvrGamepadDataFetcher);
 };
 
 }  // namespace device
 #endif  // DEVICE_VR_ANDROID_GVR_GAMEPAD_DATA_FETCHER_H_