Implement the gamepad API in the IPC proxy

content/browser/gamepad/data_fetcher.h

-// Copyright (c) 2011 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 CONTENT_BROWSER_GAMEPAD_DATA_FETCHER_H_
-#define CONTENT_BROWSER_GAMEPAD_DATA_FETCHER_H_
-
-namespace WebKit {
-class WebGamepads;
-}
-
-namespace content {
-
-class GamepadDataFetcher {
- public:
-  virtual ~GamepadDataFetcher() {}
-  virtual void GetGamepadData(WebKit::WebGamepads* pads,
-                              bool devices_changed_hint) = 0;
-  virtual void PauseHint(bool paused) {}
-};
-
-} // namespace content
-
-#endif  // CONTENT_BROWSER_GAMEPAD_DATA_FETCHER_H_