Implement the gamepad API in the IPC proxy

content/browser/gamepad/gamepad_provider.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_PROVIDER_H_
 #define CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_
 
+#include <utility>
+#include <vector>
+
+#include "base/callback_forward.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop_proxy.h"
 #include "base/shared_memory.h"
 #include "base/synchronization/lock.h"
 #include "base/system_monitor/system_monitor.h"
 #include "content/common/content_export.h"
 
 namespace base {
+class MessageLoopProxy;
 class Thread;
 }
 
 namespace content {
 
 class GamepadDataFetcher;
 struct GamepadHardwareBuffer;
 
 class CONTENT_EXPORT GamepadProvider :
   public base::SystemMonitor::DevicesChangedObserver {
  public:
-  explicit GamepadProvider();
+  GamepadProvider();
+
+  // Manually specifies the data fetcher. Used for testing.
+  explicit GamepadProvider(scoped_ptr<GamepadDataFetcher> fetcher);
+
   virtual ~GamepadProvider();
 
-  // Set the platform-specific data fetcher. Mostly used for testing.
-  void SetDataFetcher(GamepadDataFetcher* fetcher);
-
-  base::SharedMemoryHandle GetRendererSharedMemoryHandle(
+  // Returns the shared memory handle of the gamepad data duplicated into the
+  // given process.
+  base::SharedMemoryHandle GetSharedMemoryHandleForProcess(
       base::ProcessHandle renderer_process);
 
   // Pause and resume the background polling thread. Can be called from any
   // thread.
   void Pause();
   void Resume();
 
+  // Registers the given closure for calling when the user has interacted with
+  // the device. This callback will only be issued once.
+  void RegisterForUserGesture(const base::Closure& closure);
+
   // base::SystemMonitor::DevicesChangedObserver implementation.
   virtual void OnDevicesChanged(base::SystemMonitor::DeviceType type) OVERRIDE;
 
  private:
+  void Initialize(scoped_ptr<GamepadDataFetcher> fetcher);
 
   // Method for setting up the platform-specific data fetcher. Takes ownership
   // of |fetcher|.
-  void DoInitializePollingThread(GamepadDataFetcher* fetcher);
+  void DoInitializePollingThread(scoped_ptr<GamepadDataFetcher> fetcher);
 
   // Method for sending pause hints to the low-level data fetcher. Runs on
   // polling_thread_.
   void SendPauseHint(bool paused);
 
   // Method for polling a GamepadDataFetcher. Runs on the polling_thread_.
   void DoPoll();
   void ScheduleDoPoll();
 
   GamepadHardwareBuffer* SharedMemoryAsHardwareBuffer();
 
+  // Checks the gamepad state to see if the user has interacted with it.
+  void CheckForUserGesture();
+
   enum { kDesiredSamplingIntervalMs = 16 };
 
   // Keeps track of when the background thread is paused. Access to is_paused_
   // must be guarded by is_paused_lock_.
   base::Lock is_paused_lock_;
   bool is_paused_;
 
   // Keep track of when a polling task is schedlued, so as to prevent us from
   // accidentally scheduling more than one at any time, when rapidly toggling
   // |is_paused_|.
   bool have_scheduled_do_poll_;
 
+  // Lists all observers registered for user gestures, and the thread which
+  // to issue the callbacks on. Since we always issue the callback on the
+  // thread which the registration happened, and this class lives on the I/O
+  // thread, the message loop proxies will normally just be the I/O thread.
+  // However, this will be the main thread for unit testing.
+  base::Lock user_gesture_lock_;
+  struct ClosureAndThread {
+    base::Closure closure;
+    scoped_refptr<base::MessageLoopProxy> message_loop;
+  };
+  typedef std::vector<ClosureAndThread> UserGestureObserverVector;
+  UserGestureObserverVector user_gesture_observers_;
+
   // Updated based on notification from SystemMonitor when the system devices
   // have been updated, and this notification is passed on to the data fetcher
   // to enable it to avoid redundant (and possibly expensive) is-connected
   // tests. Access to devices_changed_ must be guarded by
   // devices_changed_lock_.
   base::Lock devices_changed_lock_;
   bool devices_changed_;
 
   // When polling_thread_ is running, members below are only to be used
   // from that thread.
   scoped_ptr<GamepadDataFetcher> data_fetcher_;
   base::SharedMemory gamepad_shared_memory_;
 
   // Polling is done on this background thread.
   scoped_ptr<base::Thread> polling_thread_;
 
   static GamepadProvider* instance_;
 
   DISALLOW_COPY_AND_ASSIGN(GamepadProvider);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_GAMEPAD_GAMEPAD_PROVIDER_H_