Refactor video capturing code in the render process

content/renderer/pepper/pepper_platform_video_capture.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_PEPPER_PEPPER_PLATFORM_VIDEO_CAPTURE_H_
 #define CONTENT_RENDERER_PEPPER_PEPPER_PLATFORM_VIDEO_CAPTURE_H_
 
 #include <string>
 
 #include "base/basictypes.h"
+#include "base/callback.h"
 #include "base/compiler_specific.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
-#include "media/video/capture/video_capture.h"
+#include "base/threading/thread_checker.h"
+#include "content/common/media/video_capture.h"
 #include "media/video/capture/video_capture_types.h"
 
 class GURL;
 
-namespace media {
-class VideoCaptureHandlerProxy;
-}
-
 namespace content {
 class PepperMediaDeviceManager;
 class PepperVideoCaptureHost;
 class RenderViewImpl;
-class VideoCaptureHandle;
 
-class PepperPlatformVideoCapture
-    : public media::VideoCapture,
-      public base::RefCounted<PepperPlatformVideoCapture>,
-      public media::VideoCapture::EventHandler {
+// This is a render thread only object. All methods must be accessed on
+// the render thread including cosntructor and destructor.
+class PepperPlatformVideoCapture {
  public:
   PepperPlatformVideoCapture(const base::WeakPtr<RenderViewImpl>& render_view,
                              const std::string& device_id,
                              const GURL& document_url,
                              PepperVideoCaptureHost* handler);
+  virtual ~PepperPlatformVideoCapture();
 
   // Detaches the event handler and stops sending notifications to it.
   void DetachEventHandler();
 
-  // media::VideoCapture implementation.
-  virtual void StartCapture(media::VideoCapture::EventHandler* handler,
-                            const media::VideoCaptureParams& params) OVERRIDE;
-  virtual void StopCapture(media::VideoCapture::EventHandler* handler) OVERRIDE;
-  virtual bool CaptureStarted() OVERRIDE;
-  virtual int CaptureFrameRate() OVERRIDE;
-  virtual void GetDeviceSupportedFormats(const DeviceFormatsCallback& callback)
-      OVERRIDE;
-  virtual void GetDeviceFormatsInUse(const DeviceFormatsInUseCallback& callback)
-      OVERRIDE;
-
-  // media::VideoCapture::EventHandler implementation
-  virtual void OnStarted(VideoCapture* capture) OVERRIDE;
-  virtual void OnStopped(VideoCapture* capture) OVERRIDE;
-  virtual void OnPaused(VideoCapture* capture) OVERRIDE;
-  virtual void OnError(VideoCapture* capture, int error_code) OVERRIDE;
-  virtual void OnRemoved(VideoCapture* capture) OVERRIDE;
-  virtual void OnFrameReady(VideoCapture* capture,
-                            const scoped_refptr<media::VideoFrame>& frame)
-      OVERRIDE;
-
- protected:
-  friend class base::RefCounted<PepperPlatformVideoCapture>;
-  virtual ~PepperPlatformVideoCapture();
+  void StartCapture(const media::VideoCaptureParams& params);
+  void StopCapture();
 
  private:
-  void Initialize();
-
   void OnDeviceOpened(int request_id, bool succeeded, const std::string& label);
+  void OnStateUpdate(VideoCaptureState state);
+  void OnFrameReady(
+      const scoped_refptr<media::VideoFrame>& frame,
+      const media::VideoCaptureFormat& format,
+      const base::TimeTicks& timestamp);
 
   PepperMediaDeviceManager* GetMediaDeviceManager();
 
   base::WeakPtr<RenderViewImpl> render_view_;
 
   std::string device_id_;
   std::string label_;
   int session_id_;
-
-  scoped_ptr<media::VideoCaptureHandlerProxy> handler_proxy_;
+  base::Closure release_device_cb_;
+  base::Closure stop_capture_cb_;
 
   PepperVideoCaptureHost* handler_;
 
-  scoped_ptr<VideoCaptureHandle> video_capture_;
-
-  // StartCapture() must be balanced by StopCapture(), otherwise this object
-  // will leak.
-  bool unbalanced_start_;
-
   // Whether we have a pending request to open a device. We have to make sure
   // there isn't any pending request before this object goes away.
   bool pending_open_device_;
   int pending_open_device_id_;
 
+  base::ThreadChecker thread_checker_;
+
+  base::WeakPtrFactory<PepperPlatformVideoCapture> weak_factory_;
+
   DISALLOW_COPY_AND_ASSIGN(PepperPlatformVideoCapture);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_PLATFORM_VIDEO_CAPTURE_H_