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

content/browser/renderer_host/media/video_capture_controller.h

Index: content/browser/renderer_host/media/video_capture_controller.h
diff --git a/content/browser/renderer_host/media/video_capture_controller.h b/content/browser/renderer_host/media/video_capture_controller.h
index 76e59cb29b1ab6beb719d4cf6f65f10cfd77a115..791ea42dce42ab5671d6868f6df55051264c03ba 100644
--- a/content/browser/renderer_host/media/video_capture_controller.h
+++ b/content/browser/renderer_host/media/video_capture_controller.h
@@ -134,7 +134,7 @@ class CONTENT_EXPORT VideoCaptureController : public media::VideoFrameReceiver {
       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;
@@ -149,6 +149,10 @@ class CONTENT_EXPORT VideoCaptureController : public media::VideoFrameReceiver {
         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();
@@ -158,8 +162,9 @@ class CONTENT_EXPORT VideoCaptureController : public media::VideoFrameReceiver {
     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_;
@@ -175,12 +180,20 @@ class CONTENT_EXPORT VideoCaptureController : public media::VideoFrameReceiver {
   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_;