Move the device enumerate/open/close work to device thread from IO thread

content/browser/renderer_host/media/video_capture_manager.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.
 
 // VideoCaptureManager is used to open/close, start/stop, enumerate available
 // video capture devices, and manage VideoCaptureController's.
 // All functions are expected to be called from Browser::IO thread.
 // VideoCaptureManager will open OS dependent instances of VideoCaptureDevice.
 // A device can only be opened once.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_
 
 #include <list>
 #include <map>
 
 #include "base/memory/ref_counted.h"
-#include "base/threading/thread.h"
 #include "content/browser/renderer_host/media/media_stream_provider.h"
 #include "content/common/content_export.h"
 #include "content/common/media/media_stream_options.h"
 #include "content/public/browser/browser_thread.h"
 #include "media/video/capture/video_capture_device.h"
 #include "media/video/capture/video_capture_types.h"
 
 class MockVideoCaptureManager;
 class VideoCaptureController;
 class VideoCaptureControllerEventHandler;
 
 namespace media_stream {
 
 // VideoCaptureManager opens/closes and start/stops video capture devices.
-// It is deleted on the FILE thread so that it can call base::Thread::Stop()
-// there without blocking UI/IO threads. This is also needed for incognito
-// window. When incognito window is closed, IO thread is not in shutdown mode
-// and base::Thread::Stop() can't be called on IO thread.
 class CONTENT_EXPORT VideoCaptureManager
-    : public base::RefCountedThreadSafe<VideoCaptureManager,
-          content::BrowserThread::DeleteOnFileThread>,
+    : public base::RefCountedThreadSafe<VideoCaptureManager>,
       public MediaStreamProvider {
  public:
   // Calling |Start| of this id will open the first device, even though open has
   // not been called. This is used to be able to use video capture devices
   // before MediaStream is implemented in Chrome and WebKit.
   enum { kStartOpenSessionId = 1 };
 
-  VideoCaptureManager();
+  explicit VideoCaptureManager(
+      scoped_refptr<base::MessageLoopProxy> message_loop);
 
   // Implements MediaStreamProvider.
   virtual void Register(MediaStreamProviderListener* listener) OVERRIDE;
 
   virtual void Unregister() OVERRIDE;
 
   virtual void EnumerateDevices() OVERRIDE;
 
   virtual int Open(const StreamDeviceInfo& device) OVERRIDE;
 
@@ skipping 13 matching lines @@
             base::Closure stopped_cb);
 
   // A capture device error has occurred for |capture_session_id|. The device
   // won't stream any more captured frames.
   virtual void Error(const media::VideoCaptureSessionId& capture_session_id);
 
   // Used by unit test to make sure a fake device is used instead of a real
   // video capture device. Due to timing requirements, the function must be
   // called before EnumerateDevices and Open.
   void UseFakeDevice();
-  MessageLoop* GetMessageLoop();
 
   // Called by VideoCaptureHost to get a controller for |capture_params|.
   // The controller is returned via calling |added_cb|.
   void AddController(
       const media::VideoCaptureParams& capture_params,
       VideoCaptureControllerEventHandler* handler,
       base::Callback<void(VideoCaptureController*)> added_cb);
   // Called by VideoCaptureHost to remove the |controller|.
   void RemoveController(
       VideoCaptureController* controller,
       VideoCaptureControllerEventHandler* handler);
 
  private:
   friend class ::MockVideoCaptureManager;
-  friend struct content::BrowserThread::DeleteOnThread<
-      content::BrowserThread::FILE>;
-  friend class base::DeleteHelper<VideoCaptureManager>;
-  friend class base::RefCountedThreadSafe<VideoCaptureManager,
-          content::BrowserThread::DeleteOnFileThread>;
+  friend class base::RefCountedThreadSafe<VideoCaptureManager>;
 
   virtual ~VideoCaptureManager();
 
   typedef std::list<VideoCaptureControllerEventHandler*> Handlers;
   struct Controller;
 
   // Called by the public functions, executed on vc_device_thread_.
   void OnEnumerateDevices();
   void OnOpen(int capture_session_id, const StreamDeviceInfo& device);
   void OnClose(int capture_session_id);
@@ skipping 24 matching lines @@
 
   // Helpers
   void GetAvailableDevices(media::VideoCaptureDevice::Names* device_names);
   bool DeviceOpened(const media::VideoCaptureDevice::Name& device_name);
   bool DeviceInUse(const media::VideoCaptureDevice* video_capture_device);
   media::VideoCaptureDevice* GetOpenedDevice(
       const StreamDeviceInfo& device_info);
   bool IsOnCaptureDeviceThread() const;
   media::VideoCaptureDevice* GetDeviceInternal(int capture_session_id);
 
-  // Thread for all calls to VideoCaptureDevice.
-  base::Thread vc_device_thread_;
+  // The message loop of media stream device thread that this object runs on.
+  scoped_refptr<base::MessageLoopProxy> message_loop_;
 
   // Only accessed on Browser::IO thread.
   MediaStreamProviderListener* listener_;
   int new_capture_session_id_;
 
   // Only accessed from vc_device_thread_.
   // VideoCaptureManager owns all VideoCaptureDevices and is responsible for
   // deleting the instances when they are not used any longer.
   typedef std::map<int, media::VideoCaptureDevice*> VideoCaptureDevices;
   VideoCaptureDevices devices_;
 
   // Set to true if using fake devices for testing, false by default.
   bool use_fake_device_;
 
   // Only accessed from vc_device_thread_.
   // VideoCaptureManager owns all VideoCaptureController's and is responsible
   // for deleting the instances when they are not used any longer.
   // VideoCaptureDevice is one-to-one mapped to VideoCaptureController.
   typedef std::map<media::VideoCaptureDevice*, Controller*> Controllers;
   Controllers controllers_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureManager);
 };
 
 }  // namespace media_stream
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_MANAGER_H_