[Mojo Video Capture] Retire buffers when Android Chromium goes to the background

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 116 matching lines @@
   const media::VideoCaptureFormat& GetVideoCaptureFormat() const;
 
   bool has_received_frames() const { return has_received_frames_; }
 
   // Implementation of media::VideoFrameReceiver interface:
   void OnIncomingCapturedVideoFrame(
       media::VideoCaptureDevice::Client::Buffer buffer,
       scoped_refptr<media::VideoFrame> frame) override;
   void OnError() override;
   void OnLog(const std::string& message) override;
-  void OnBufferDestroyed(int buffer_id_to_drop) override;
+  void OnBufferRetired(int buffer_id) override;
 
  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,
         media::FrameBufferPool* frame_buffer_pool);
     ~BufferState();
     BufferState(const BufferState& other);
+    BufferState& operator=(const BufferState& other);
+    int buffer_id() const { return buffer_id_; }
+    bool is_retired() const { return is_retired_; }
+    void set_is_retired() { is_retired_ = true; }
     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_;
+    int buffer_id_;
+    bool is_retired_ = false;
+    int frame_feedback_id_;
     media::VideoFrameConsumerFeedbackObserver* consumer_feedback_observer_;
     media::FrameBufferPool* frame_buffer_pool_;
     double max_consumer_utilization_;
     int consumer_hold_count_;
   };
 
   // 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);
 
+  std::vector<BufferState>::iterator FindBufferState(int buffer_id);
+
+  void OnClientFinishedConsumingBuffer(ControllerClient* client,
+                                       int buffer_id,
+                                       double consumer_resource_utilization);
+  void ReleaseBufferState(
+      const std::vector<BufferState>::iterator& buffer_state_iter);
+
   std::unique_ptr<media::FrameBufferPool> frame_buffer_pool_;
 
   std::unique_ptr<media::VideoFrameConsumerFeedbackObserver>
       consumer_feedback_observer_;
 
-  std::map<int, BufferState> buffer_id_to_state_map_;
+  std::vector<BufferState> buffer_states_;
 
   // 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_