[Mojo Video Capture] Replace RESOURCE_UTILIZATION with interface ReceiverLoadObserver

media/capture/content/thread_safe_capture_oracle.cc

 // Copyright 2014 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.
 
 #include "media/capture/content/thread_safe_capture_oracle.h"
 
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
@@ skipping 210 matching lines @@
                                  params_.requested_format.frame_rate);
     frame->metadata()->SetTimeTicks(VideoFrameMetadata::CAPTURE_BEGIN_TIME,
                                     capture_begin_time);
     frame->metadata()->SetTimeTicks(VideoFrameMetadata::CAPTURE_END_TIME,
                                     base::TimeTicks::Now());
     frame->metadata()->SetTimeDelta(VideoFrameMetadata::FRAME_DURATION,
                                     estimated_frame_duration);
     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