Refactored gamepad polling to support dynamic sources

device/gamepad/gamepad_platform_data_fetcher_android.h

 // Copyright 2014 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.
 
 // Define the data fetcher that GamepadProvider will use for android port.
 // (GamepadPlatformDataFetcher).
 
 #ifndef DEVICE_GAMEPAD_GAMEPAD_PLATFORM_DATA_FETCHER_ANDROID_H_
 #define DEVICE_GAMEPAD_GAMEPAD_PLATFORM_DATA_FETCHER_ANDROID_H_
 
 #include <jni.h>
 
 #include "base/android/jni_android.h"
 #include "base/macros.h"
 #include "device/gamepad/gamepad_data_fetcher.h"
 #include "device/gamepad/gamepad_provider.h"
 #include "device/gamepad/gamepad_standard_mappings.h"
 #include "third_party/WebKit/public/platform/WebGamepads.h"
 
 namespace device {
 
 class GamepadPlatformDataFetcherAndroid : public GamepadDataFetcher {
  public:
+  typedef GamepadDataFetcherFactoryImpl<GamepadPlatformDataFetcherAndroid,
+                                        GAMEPAD_SOURCE_ANDROID>
+      Factory;
+
   GamepadPlatformDataFetcherAndroid();
   ~GamepadPlatformDataFetcherAndroid() override;
 
+  GamepadSource source() override;
+
   void PauseHint(bool paused) override;
 
-  void GetGamepadData(blink::WebGamepads* pads,
-                      bool devices_changed_hint) override;
+  void GetGamepadData(bool devices_changed_hint) override;
 
   // Registers the JNI methods for GamepadsReader.
   static bool RegisterGamepadPlatformDataFetcherAndroid(JNIEnv* env);
 
  private:
+  void OnAddedToProvider() override;
+
   DISALLOW_COPY_AND_ASSIGN(GamepadPlatformDataFetcherAndroid);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_GAMEPAD_GAMEPAD_PLATFORM_DATA_FETCHER_ANDROID_H_