Revert of Refactor video capturing code in the render process

content/renderer/media/video_capture_impl.h

Index: content/renderer/media/video_capture_impl.h
diff --git a/content/renderer/media/video_capture_impl.h b/content/renderer/media/video_capture_impl.h
index 66c393c7d81026f22a3e4b0ae2d93bfe54b79cd3..7988669b9def53d82a2c4f5852b8ccdc19953273 100644
--- a/content/renderer/media/video_capture_impl.h
+++ b/content/renderer/media/video_capture_impl.h
@@ -10,12 +10,20 @@
 // operation of a capture device to the browser process and receives responses
 // from browser process.
 //
-// VideoCaptureImpl is an IO thread only object. See the comments in
-// video_capture_impl_manager.cc for the lifetime of this object.
-// All methods must be called on the IO thread.
+// All public methods of VideoCaptureImpl can be called on any thread.
+// Internally it runs on the IO thread. Clients of this class implement
+// interface media::VideoCapture::EventHandler which is called only on the IO
+// thread.
 //
-// This is an internal class used by VideoCaptureImplManager only. Do not access
-// this directly.
+// Implementation note: tasks are posted bound to Unretained(this) to the I/O
+// thread and this is safe (even though the I/O thread is scoped to the renderer
+// process) because VideoCaptureImplManager only triggers deletion of its
+// VideoCaptureImpl's by calling DeInit which detours through the I/O thread, so
+// as long as nobody posts tasks after the DeInit() call is made, it is
+// guaranteed none of these Unretained posted tasks will dangle after the delete
+// goes through. The "as long as" is guaranteed by clients of
+// VideoCaptureImplManager not using devices after they've released
+// VideoCaptureHandle, which is a wrapper of this object.
 
 #ifndef CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_
 #define CONTENT_RENDERER_MEDIA_VIDEO_CAPTURE_IMPL_H_
@@ -24,10 +32,10 @@
 #include <map>
 
 #include "base/memory/weak_ptr.h"
-#include "base/threading/thread_checker.h"
 #include "content/common/content_export.h"
 #include "content/common/media/video_capture.h"
 #include "content/renderer/media/video_capture_message_filter.h"
+#include "media/video/capture/video_capture.h"
 #include "media/video/capture/video_capture_types.h"
 
 namespace base {
@@ -38,52 +46,35 @@
 struct MailboxHolder;
 }  // namespace gpu
 
-namespace media {
-class VideoFrame;
-}  // namespace media
-
 namespace content {
 
 class CONTENT_EXPORT VideoCaptureImpl
-    : public VideoCaptureMessageFilter::Delegate {
+    : public media::VideoCapture, public VideoCaptureMessageFilter::Delegate {
  public:
-  virtual ~VideoCaptureImpl();
-
   VideoCaptureImpl(media::VideoCaptureSessionId session_id,
                    VideoCaptureMessageFilter* filter);
+  virtual ~VideoCaptureImpl();
 
   // Start listening to IPC messages.
   void Init();
 
-  // Stop listening to IPC messages.
-  void DeInit();
+  // Stop listening to IPC messages. Call |done_cb| when done.
+  void DeInit(base::Closure done_cb);
 
   // Stop/resume delivering video frames to clients, based on flag |suspend|.
   void SuspendCapture(bool suspend);
 
-  // Start capturing using the provided parameters.
-  // |client_id| must be unique to this object in the render process. It is
-  // used later to stop receiving video frames.
-  // |state_update_cb| will be called when state changes.
-  // |deliver_frame_cb| will be called when a frame is ready.
-  void StartCapture(
-      int client_id,
-      const media::VideoCaptureParams& params,
-      const VideoCaptureStateUpdateCB& state_update_cb,
-      const VideoCaptureDeliverFrameCB& deliver_frame_cb);
-
-  // Stop capturing. |client_id| is the identifier used to call StartCapture.
-  void StopCapture(int client_id);
-
-  // Get capturing formats supported by this device.
-  // |callback| will be invoked with the results.
-  void GetDeviceSupportedFormats(
-      const VideoCaptureDeviceFormatsCB& callback);
-
-  // Get capturing formats currently in use by this device.
-  // |callback| will be invoked with the results.
-  void GetDeviceFormatsInUse(
-      const VideoCaptureDeviceFormatsCB& callback);
+  // media::VideoCapture interface.
+  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::VideoCaptureSessionId session_id() const { return session_id_; }
 
@@ -91,20 +82,21 @@
   friend class VideoCaptureImplTest;
   friend class MockVideoCaptureImpl;
 
-  // Carries a shared memory for transferring video frames from browser to
-  // renderer.
   class ClientBuffer;
+  typedef std::map<media::VideoCapture::EventHandler*,
+                   media::VideoCaptureParams> ClientInfo;
 
-  // Contains information for a video capture client. Including parameters
-  // for capturing and callbacks to the client.
-  struct ClientInfo {
-    ClientInfo();
-    ~ClientInfo();
-    media::VideoCaptureParams params;
-    VideoCaptureStateUpdateCB state_update_cb;
-    VideoCaptureDeliverFrameCB deliver_frame_cb;
-  };
-  typedef std::map<int, ClientInfo> ClientInfoMap;
+  void InitOnIOThread();
+  void DeInitOnIOThread(base::Closure done_cb);
+  void SuspendCaptureOnIOThread(bool suspend);
+  void StartCaptureOnIOThread(
+      media::VideoCapture::EventHandler* handler,
+      const media::VideoCaptureParams& params);
+  void StopCaptureOnIOThread(media::VideoCapture::EventHandler* handler);
+  void GetDeviceSupportedFormatsOnIOThread(
+      const DeviceFormatsCallback& callback);
+  void GetDeviceFormatsInUseOnIOThread(
+      const DeviceFormatsInUseCallback& callback);
 
   // VideoCaptureMessageFilter::Delegate interface.
   virtual void OnBufferCreated(base::SharedMemoryHandle handle,
@@ -138,26 +130,28 @@
   virtual void Send(IPC::Message* message);
 
   // Helpers.
-  bool RemoveClient(int client_id, ClientInfoMap* clients);
+  bool RemoveClient(media::VideoCapture::EventHandler* handler,
+                    ClientInfo* clients);
 
   const scoped_refptr<VideoCaptureMessageFilter> message_filter_;
+  const scoped_refptr<base::MessageLoopProxy> io_message_loop_proxy_;
   int device_id_;
   const int session_id_;
 
   // Vector of callbacks to be notified of device format enumerations, used only
   // on IO Thread.
-  std::vector<VideoCaptureDeviceFormatsCB> device_formats_cb_queue_;
+  std::vector<DeviceFormatsCallback> device_formats_callback_queue_;
   // Vector of callbacks to be notified of a device's in use capture format(s),
   // used only on IO Thread.
-  std::vector<VideoCaptureDeviceFormatsCB> device_formats_in_use_cb_queue_;
+  std::vector<DeviceFormatsInUseCallback> device_formats_in_use_callback_queue_;
 
   // Buffers available for sending to the client.
   typedef std::map<int32, scoped_refptr<ClientBuffer> > ClientBufferMap;
   ClientBufferMap client_buffers_;
 
-  ClientInfoMap clients_;
-  ClientInfoMap clients_pending_on_filter_;
-  ClientInfoMap clients_pending_on_restart_;
+  ClientInfo clients_;
+  ClientInfo clients_pending_on_filter_;
+  ClientInfo clients_pending_on_restart_;
 
   // Member params_ represents the video format requested by the
   // client to this class via StartCapture().
@@ -172,9 +166,6 @@
   bool suspended_;
   VideoCaptureState state_;
 
-  // |weak_factory_| and |thread_checker_| are bound to the IO thread.
-  base::ThreadChecker thread_checker_;
-
   // WeakPtrFactory pointing back to |this| object, for use with
   // media::VideoFrames constructed in OnBufferReceived() from buffers cached
   // in |client_buffers_|.