RESOURCE_UTILIZATION in VideoFrameMetadata, a consumer feedback signal.

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 51933a87d1a705e831b12e5ce73b062e2c4cdee2..77d03729a5ec0c5ada07f94fc3190b1b71b00cbc 100644
--- a/content/renderer/media/video_capture_impl.h
+++ b/content/renderer/media/video_capture_impl.h
@@ -129,7 +129,8 @@ class CONTENT_EXPORT VideoCaptureImpl
   // buffer.
   void OnClientBufferFinished(int buffer_id,
                               const scoped_refptr<ClientBuffer>& buffer,
-                              uint32 release_sync_point);
+                              uint32 release_sync_point,
+                              double consumer_stress_level);
 
   void StopDevice();
   void RestartCapture();
@@ -140,6 +141,15 @@ class CONTENT_EXPORT VideoCaptureImpl
   // Helpers.
   bool RemoveClient(int client_id, ClientInfoMap* clients);
 
+  // Called (by an unknown thread) when all consumers are done with a VideoFrame
+  // and its ref-count has gone to zero.  This helper function grabs the
+  // STRESS_LEVEL value from the |metadata| and then runs the given callback, to
+  // trampoline back to the IO thread with the values.
+  static void DidFinishConsumingFrame(
+    const media::VideoFrameMetadata* metadata,
+    uint32* release_sync_point_storage,  // Takes ownership.
+    const base::Callback<void(uint32, double)>& callback_to_io_thread);
+
   const scoped_refptr<VideoCaptureMessageFilter> message_filter_;
   int device_id_;
   const int session_id_;