Implement the gamepad API in the IPC proxy

content/browser/gamepad/gamepad_platform_data_fetcher_win.h

+// Copyright (c) 2012 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_GAMEPAD_PLATFORM_DATA_FETCHER_WIN_H_
+#define CONTENT_BROWSER_GAMEPAD_GAMEPAD_PLATFORM_DATA_FETCHER_WIN_H_
+
+#include "build/build_config.h"
+
+#ifndef WIN32_LEAN_AND_MEAN
+#define WIN32_LEAN_AND_MEAN
+#endif
+#include <windows.h>
+#include <XInput.h>
+
+#include "base/basictypes.h"
+#include "base/compiler_specific.h"
+#include "base/scoped_native_library.h"
+#include "content/browser/gamepad/gamepad_data_fetcher.h"
+
+namespace content {
+
+class GamepadPlatformDataFetcherWin : public GamepadDataFetcher {
+ public:
+  GamepadPlatformDataFetcherWin();
+  virtual ~GamepadPlatformDataFetcherWin();
+  virtual void GetGamepadData(WebKit::WebGamepads* pads,
+                              bool devices_changed_hint) OVERRIDE;
+ private:
+  // The three function types we use from xinput1_3.dll.
+  typedef void (WINAPI *XInputEnableFunc)(BOOL enable);
+  typedef DWORD (WINAPI *XInputGetCapabilitiesFunc)(
+    DWORD dwUserIndex, DWORD dwFlags, XINPUT_CAPABILITIES* pCapabilities);
+  typedef DWORD (WINAPI *XInputGetStateFunc)(
+      DWORD dwUserIndex, XINPUT_STATE* pState);
+
+  // Get functions from dynamically loaded xinput1_3.dll. We don't use
+  // DELAYLOAD because the import library for Win8 SDK pulls xinput1_4 which
+  // isn't redistributable. Returns true if loading was successful. We include
+  // xinput1_3.dll with Chrome.
+  bool GetXinputDllFunctions();
+
+  base::ScopedNativeLibrary xinput_dll_;
+  bool xinput_available_;
+
+  // Function pointers to XInput functionality, retrieved in
+  // |GetXinputDllFunctions|.
+  XInputEnableFunc xinput_enable_;
+  XInputGetCapabilitiesFunc xinput_get_capabilities_;
+  XInputGetStateFunc xinput_get_state_;
+
+  DISALLOW_COPY_AND_ASSIGN(GamepadPlatformDataFetcherWin);
+};
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_PLATFORM_DATA_FETCHER_WIN_H_