Linux: Refactor udev device monitoring code into its own class so it can be reused more easily.

content/browser/gamepad/platform_data_fetcher_linux.h

Index: content/browser/gamepad/platform_data_fetcher_linux.h
===================================================================
--- content/browser/gamepad/platform_data_fetcher_linux.h	(revision 148200)
+++ content/browser/gamepad/platform_data_fetcher_linux.h	(working copy)
@@ -9,47 +9,31 @@
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
-#include "base/message_pump_libevent.h"
-#include "build/build_config.h"
 #include "content/browser/gamepad/data_fetcher.h"
 #include "content/browser/gamepad/gamepad_standard_mappings.h"
+#include "content/browser/udev_linux.h"
 #include "third_party/WebKit/Source/WebKit/chromium/public/platform/WebGamepads.h"
 
-extern "C" {
-struct udev;
-struct udev_device;
-struct udev_monitor;
-}
-
 namespace content {
 
-class GamepadPlatformDataFetcherLinux :
-    public GamepadDataFetcher,
-    public base::MessagePumpLibevent::Watcher {
+class GamepadPlatformDataFetcherLinux : public GamepadDataFetcher,
+                                        public UdevLinux {
  public:
   GamepadPlatformDataFetcherLinux();
   virtual ~GamepadPlatformDataFetcherLinux();
 
-  // GamepadDataFetcher:
+  // GamepadDataFetcher implementation.
   virtual void GetGamepadData(WebKit::WebGamepads* pads,
                               bool devices_changed_hint) OVERRIDE;
 
-  // base::MessagePump:Libevent::Watcher:
-  virtual void OnFileCanReadWithoutBlocking(int fd) OVERRIDE;
-  virtual void OnFileCanWriteWithoutBlocking(int fd) OVERRIDE;
+  // UdevLinux implementation.
+  virtual void Notify(udev_device* device) OVERRIDE;
 
  private:
   void RefreshDevice(udev_device* dev);
   void EnumerateDevices();
   void ReadDeviceData(size_t index);
 
-  // libudev-related items, the main context, and the monitoring context to be
-  // notified about changes to device states.
-  udev* udev_;
-  udev_monitor* monitor_;
-  int monitor_fd_;
-  base::MessagePumpLibevent::FileDescriptorWatcher monitor_watcher_;
-
   // File descriptors for the /dev/input/js* devices. -1 if not in use.
   int device_fds_[WebKit::WebGamepads::itemsLengthCap];