[Mojo Video Capture] Replace RESOURCE_UTILIZATION with interface ReceiverLoadObserver

media/capture/content/thread_safe_capture_oracle.cc

Index: media/capture/content/thread_safe_capture_oracle.cc
diff --git a/media/capture/content/thread_safe_capture_oracle.cc b/media/capture/content/thread_safe_capture_oracle.cc
index c406396eea8e57d70ce35ccab6d4e8e379a08490..4393606a64c58628e49a6fb0c9281bad3cef6dd5 100644
--- a/media/capture/content/thread_safe_capture_oracle.cc
+++ b/media/capture/content/thread_safe_capture_oracle.cc
@@ -228,25 +228,16 @@ void ThreadSafeCaptureOracle::DidCaptureFrame(
     frame->metadata()->SetTimeTicks(VideoFrameMetadata::REFERENCE_TIME,
                                     reference_time);
 
-    frame->AddDestructionObserver(
-        base::Bind(&ThreadSafeCaptureOracle::DidConsumeFrame, this,
-                   frame_number, frame->metadata()));
-
-    client_->OnIncomingCapturedVideoFrame(std::move(buffer), std::move(frame));
+    client_->OnIncomingCapturedVideoFrame(std::move(buffer), std::move(frame),
+                                          frame_number);
   }
 }
 
-void ThreadSafeCaptureOracle::DidConsumeFrame(
+void ThreadSafeCaptureOracle::OnConsumerReportingUtilization(
     int frame_number,
-    const media::VideoFrameMetadata* metadata) {
-  // Note: This function may be called on any thread by the VideoFrame
-  // destructor.  |metadata| is still valid for read-access at this point.
-  double utilization = -1.0;
-  if (metadata->GetDouble(media::VideoFrameMetadata::RESOURCE_UTILIZATION,
-                          &utilization)) {
-    base::AutoLock guard(lock_);
-    oracle_.RecordConsumerFeedback(frame_number, utilization);
-  }
+    double utilization) {
+  base::AutoLock guard(lock_);

[miu, 2016/12/01 05:25:18]

One of these days, I'm going to have to go through all this code and fix the
threading model; and get rid of all the mutexes. ;-) It has, over a long history
and many authors, evolved to this point.

[chfremer, 2016/12/02 01:28:28]

I hope it helps that calls to this method are now guaranteed to arrive from the
"device thread" (assuming no additional thread hopping happens between the
interface media::VideoCaptureDevice and here).

+  oracle_.RecordConsumerFeedback(frame_number, utilization);
 }
 
 }  // namespace media