Add gamepad data fetcher for Linux

content/browser/gamepad/gamepad_provider.cc

Index: content/browser/gamepad/gamepad_provider.cc
diff --git a/content/browser/gamepad/gamepad_provider.cc b/content/browser/gamepad/gamepad_provider.cc
index 54d38a573c73f6abbd30b203881613d225b37d64..0b4144599ae7c0c49bff83cd431bf2db8c932df5 100644
--- a/content/browser/gamepad/gamepad_provider.cc
+++ b/content/browser/gamepad/gamepad_provider.cc
@@ -12,41 +12,14 @@
 #include "base/task.h"
 #include "base/threading/thread.h"
 #include "base/threading/thread_restrictions.h"
-#include "content/public/browser/browser_thread.h"
-#include "content/browser/gamepad/gamepad_provider.h"
 #include "content/browser/gamepad/data_fetcher.h"
+#include "content/browser/gamepad/gamepad_provider.h"
+#include "content/browser/gamepad/platform_data_fetcher.h"
 #include "content/common/gamepad_messages.h"
-
-#if defined(OS_WIN)
-#include "content/browser/gamepad/data_fetcher_win.h"
-#elif defined(OS_MACOSX)
-#include "content/browser/gamepad/data_fetcher_mac.h"
-#endif
+#include "content/public/browser/browser_thread.h"
 
 namespace content {
 
-// Define the default data fetcher that GamepadProvider will use if none is
-// supplied. (GamepadPlatformDataFetcher).
-#if defined(OS_WIN)
-
-typedef GamepadDataFetcherWindows GamepadPlatformDataFetcher;
-
-#elif defined(OS_MACOSX)
-
-typedef GamepadDataFetcherMac GamepadPlatformDataFetcher;
-
-#else
-
-class GamepadEmptyDataFetcher : public GamepadDataFetcher {
- public:
-  void GetGamepadData(WebKit::WebGamepads* pads, bool) {
-    pads->length = 0;
-  }
-};
-typedef GamepadEmptyDataFetcher GamepadPlatformDataFetcher;
-
-#endif
-
 GamepadProvider::GamepadProvider(GamepadDataFetcher* fetcher)
     : is_paused_(false),
       devices_changed_(true),