Eliminate video capture thread in renderer

content/renderer/media/rtc_video_capture_delegate.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_RENDERER_MEDIA_RTC_VIDEO_CAPTURE_DELEGATE_H_
 #define CONTENT_RENDERER_MEDIA_RTC_VIDEO_CAPTURE_DELEGATE_H_
 
 #include "base/callback.h"
 #include "base/message_loop/message_loop_proxy.h"
 #include "content/common/media/video_capture.h"
-#include "content/renderer/media/video_capture_impl_manager.h"
 #include "media/video/capture/video_capture.h"
 
 namespace content {
 
+class VideoCaptureHandle;
+
 // Implements a simple reference counted video capturer that guarantees that
 // methods in RtcVideoCaptureDelegateEventHandler is only called from when
 // StartCapture have been called until after StopCapture have been called.
 // It uses VideoCaptureImplManager to start / stop and receive I420 frames
 // from Chrome's video capture implementation.
 class RtcVideoCaptureDelegate
     : public base::RefCountedThreadSafe<RtcVideoCaptureDelegate>,
       public media::VideoCapture::EventHandler {
  public:
   enum CaptureState {
     CAPTURE_STOPPED,  // The capturer has been stopped or hasn't started yet.
     CAPTURE_RUNNING,  // The capturer has been started successfully and is now
                       // capturing.
     CAPTURE_FAILED,  // The capturer failed to start.
   };
 
   typedef base::Callback<void(const scoped_refptr<media::VideoFrame>&)>
       FrameCapturedCallback;
   typedef base::Callback<void(CaptureState)> StateChangeCallback;
 
-  RtcVideoCaptureDelegate(const media::VideoCaptureSessionId id,
-                          VideoCaptureImplManager* vc_manager);
+  RtcVideoCaptureDelegate(const media::VideoCaptureSessionId id);
 
   void StartCapture(const media::VideoCaptureParams& params,
                     const FrameCapturedCallback& captured_callback,
                     const StateChangeCallback& state_callback);
   void StopCapture();
 
+ protected:
   // media::VideoCapture::EventHandler implementation.
-  // These functions are called from a thread owned by |vc_manager_|.
+  // These functions are called on the IO thread (same as where
+  // |capture_engine_| runs).
   virtual void OnStarted(media::VideoCapture* capture) OVERRIDE;
   virtual void OnStopped(media::VideoCapture* capture) OVERRIDE;
   virtual void OnPaused(media::VideoCapture* capture) OVERRIDE;
   virtual void OnError(media::VideoCapture* capture, int error_code) OVERRIDE;
   virtual void OnRemoved(media::VideoCapture* capture) OVERRIDE;
   virtual void OnFrameReady(
       media::VideoCapture* capture,
       const scoped_refptr<media::VideoFrame>& frame) OVERRIDE;
 
  private:
   friend class base::RefCountedThreadSafe<RtcVideoCaptureDelegate>;
 
   virtual ~RtcVideoCaptureDelegate();
 
   void OnFrameReadyOnCaptureThread(
       media::VideoCapture* capture,
       const scoped_refptr<media::VideoFrame>& frame);
   void OnErrorOnCaptureThread(media::VideoCapture* capture);
   void OnRemovedOnCaptureThread(media::VideoCapture* capture);
 
   // The id identifies which video capture device is used for this video
   // capture session.
   media::VideoCaptureSessionId session_id_;
-  // The video capture manager handles open/close of video capture devices.
-  scoped_refptr<VideoCaptureImplManager> vc_manager_;
-  media::VideoCapture* capture_engine_;
+  scoped_ptr<VideoCaptureHandle> capture_engine_;
 
   // Accessed on the thread where StartCapture is called.
   bool got_first_frame_;
   bool error_occured_;
 
   // |captured_callback_| is provided to this class in StartCapture and must be
   // valid until StopCapture is called.
   FrameCapturedCallback captured_callback_;
   // |state_callback_| is provided to this class in StartCapture and must be
   // valid until StopCapture is called.
   StateChangeCallback state_callback_;
   // Message loop of the caller of StartCapture.
   scoped_refptr<base::MessageLoopProxy> message_loop_proxy_;
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_MEDIA_RTC_VIDEO_CAPTURE_DELEGATE_H_