Add gamepad data fetcher for Linux

content/browser/gamepad/platform_data_fetcher.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.
+
+// Define the default data fetcher that GamepadProvider will use if none is
+// supplied. (GamepadPlatformDataFetcher).
+
+#ifndef CONTENT_BROWSER_GAMEPAD_PLATFORM_DATA_FETCHER_H_
+#define CONTENT_BROWSER_GAMEPAD_PLATFORM_DATA_FETCHER_H_
+
+#if defined(OS_WIN)
+#include "content/browser/gamepad/platform_data_fetcher_win.h"
+#elif defined(OS_MACOSX)
+#include "content/browser/gamepad/platform_data_fetcher_mac.h"
+#elif defined(OS_LINUX)
+#include "content/browser/gamepad/platform_data_fetcher_linux.h"
+#endif
+
+namespace content {
+
+#if defined(OS_WIN)
+
+typedef GamepadPlatformDataFetcherWin GamepadPlatformDataFetcher;
+
+#elif defined(OS_MACOSX)
+
+typedef GamepadPlatformDataFetcherMac GamepadPlatformDataFetcher;
+
+#elif defined(OS_LINUX)
+
+typedef GamepadPlatformDataFetcherLinux GamepadPlatformDataFetcher;
+
+#else
+
+class GamepadDataFetcherEmpty : public GamepadDataFetcher {
+ public:
+  void GetGamepadData(WebKit::WebGamepads* pads, bool) {
+    pads->length = 0;
+  }
+};
+typedef GamepadDataFetcherEmpty GamepadPlatformDataFetcher;
+
+#endif
+
+}  // namespace content
+
+#endif  // CONTENT_BROWSER_GAMEPAD_PLATFORM_DATA_FETCHER_H_