[Mojo Video Capture] Decouple VCController from VCBufferPool and VCDeviceClient

content/browser/renderer_host/media/video_capture_controller.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.
 //
 // VideoCaptureController is the glue between a VideoCaptureDevice and all
 // VideoCaptureHosts that have connected to it. A controller exists on behalf of
 // one (and only one) VideoCaptureDevice; both are owned by the
 // VideoCaptureManager.
 //
 // The VideoCaptureController is responsible for:
@@ skipping 37 matching lines @@
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "base/process/process.h"
 #include "content/browser/renderer_host/media/video_capture_controller_event_handler.h"
 #include "content/common/content_export.h"
 #include "content/common/media/video_capture.h"
 #include "media/capture/video/video_frame_receiver.h"
 #include "media/capture/video_capture_types.h"
 
 namespace media {
-class VideoCaptureBufferPool;
+class FrameBufferPool;
 }
 
 namespace content {
 
 class CONTENT_EXPORT VideoCaptureController : public media::VideoFrameReceiver {
  public:
-  // |max_buffers| is the maximum number of video frame buffers in-flight at any
-  // one time.  This value should be based on the logical capacity of the
-  // capture pipeline, and not on hardware performance.  For example, tab
-  // capture requires more buffers than webcam capture because the pipeline is
-  // longer (it includes read-backs pending in the GPU pipeline).
-  explicit VideoCaptureController(int max_buffers);
+  explicit VideoCaptureController();

[miu, 2016/12/13 21:11:10]

No longer need 'explicit' here.

[chfremer, 2016/12/13 23:12:39]

Done.

   ~VideoCaptureController() override;
 
   base::WeakPtr<VideoCaptureController> GetWeakPtrForIOThread();
 
+  // Factory code creating instances of VideoCaptureController must set a
+  // FrameBufferPool before any of the media::VideoFrameReceiver are used.
+  // Setting the observer is done in this method separate from the constructor
+  // in order to allow use the media::VideoFrameReceiver methods
+  // before the observer can be provided. (This is the case with
+  // VideoCaptureManager).
+  void SetFrameBufferPool(
+      std::unique_ptr<media::FrameBufferPool> frame_buffer_pool);
+
   // Factory code creating instances of VideoCaptureController may optionally
   // set a VideoFrameConsumerFeedbackObserver. Setting the observer is done in
   // this method separate from the constructor to allow clients to create and
   // use instances before they can provide the observer. (This is the case with
   // VideoCaptureManager).
   void SetConsumerFeedbackObserver(
       std::unique_ptr<media::VideoFrameConsumerFeedbackObserver> observer);
 
-  // Return a new VideoCaptureDeviceClient to forward capture events to this
-  // instance.
-  std::unique_ptr<media::VideoCaptureDevice::Client> NewDeviceClient();
-
   // Start video capturing and try to use the resolution specified in |params|.
   // Buffers will be shared to the client as necessary. The client will continue
   // to receive frames from the device until RemoveClient() is called.
   void AddClient(VideoCaptureControllerID id,
                  VideoCaptureControllerEventHandler* event_handler,
                  media::VideoCaptureSessionId session_id,
                  const media::VideoCaptureParams& params);
 
   // Stop video capture. This will take back all buffers held by by
   // |event_handler|, and |event_handler| shouldn't use those buffers any more.
@@ skipping 49 matching lines @@
  private:
   struct ControllerClient;
   typedef std::list<std::unique_ptr<ControllerClient>> ControllerClients;
 
   class BufferState {
    public:
     explicit BufferState(
         int buffer_id,
         int frame_feedback_id,
         media::VideoFrameConsumerFeedbackObserver* consumer_feedback_observer,
-        scoped_refptr<media::VideoCaptureBufferPool> buffer_pool,
+        media::FrameBufferPool* frame_buffer_pool,
         scoped_refptr<media::VideoFrame> frame);
     ~BufferState();
     BufferState(const BufferState& other);
     void RecordConsumerUtilization(double utilization);
     void IncreaseConsumerCount();
     void DecreaseConsumerCount();
     bool HasZeroConsumerHoldCount();
     void SetConsumerFeedbackObserver(
         media::VideoFrameConsumerFeedbackObserver* consumer_feedback_observer);
+    void SetFrameBufferPool(media::FrameBufferPool* frame_buffer_pool);
 
    private:
     const int buffer_id_;
     const int frame_feedback_id_;
     media::VideoFrameConsumerFeedbackObserver* consumer_feedback_observer_;
-    const scoped_refptr<media::VideoCaptureBufferPool> buffer_pool_;
+    media::FrameBufferPool* frame_buffer_pool_;
     const scoped_refptr<media::VideoFrame> frame_;
     double max_consumer_utilization_;
     int consumer_hold_count_;
   };
 
   // Notify renderer that a new buffer has been created.
   void DoNewBufferOnIOThread(ControllerClient* client,
                              media::VideoCaptureDevice::Client::Buffer* buffer,
                              const scoped_refptr<media::VideoFrame>& frame);
 
   // Find a client of |id| and |handler| in |clients|.
   ControllerClient* FindClient(VideoCaptureControllerID id,
                                VideoCaptureControllerEventHandler* handler,
                                const ControllerClients& clients);
 
   // Find a client of |session_id| in |clients|.
   ControllerClient* FindClient(int session_id,
                                const ControllerClients& clients);
 
-  // The pool of shared-memory buffers used for capturing.
-  const scoped_refptr<media::VideoCaptureBufferPool> buffer_pool_;
+  std::unique_ptr<media::FrameBufferPool> frame_buffer_pool_;

[miu, 2016/12/13 21:11:10]

Nice! Removing the ref-counting is a good sign the object graph has just become
more "untangled." :)

I'm aware the VCBufferPool is still ref-counted, but that's fine since it's
representing a shared data resource, and the ref-counting has been limited to
internal implementation (in the VCManager module).

[chfremer, 2016/12/13 23:12:39]

Acknowledged.

 
   std::unique_ptr<media::VideoFrameConsumerFeedbackObserver>
       consumer_feedback_observer_;
 
   std::map<int, BufferState> buffer_id_to_state_map_;
 
   // All clients served by this controller.
   ControllerClients controller_clients_;
 
   // Takes on only the states 'STARTED' and 'ERROR'. 'ERROR' is an absorbing
   // state which stops the flow of data to clients.
   VideoCaptureState state_;
 
   // True if the controller has received a video frame from the device.
   bool has_received_frames_;
 
   media::VideoCaptureFormat video_capture_format_;
 
   base::WeakPtrFactory<VideoCaptureController> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoCaptureController);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_MEDIA_VIDEO_CAPTURE_CONTROLLER_H_