[Mojo Video Capture] Replace RESOURCE_UTILIZATION with interface ReceiverLoadObserver

media/capture/content/screen_capture_device_core.cc

Index: media/capture/content/screen_capture_device_core.cc
diff --git a/media/capture/content/screen_capture_device_core.cc b/media/capture/content/screen_capture_device_core.cc
index f65ea591741117b68c4a1cc5b9487d896e5b083e..d42c8d69a2471c618aa89a1bfc9b43da3ad1920f 100644
--- a/media/capture/content/screen_capture_device_core.cc
+++ b/media/capture/content/screen_capture_device_core.cc
@@ -113,6 +113,12 @@ void ScreenCaptureDeviceCore::StopAndDeAllocate() {
   capture_machine_->Stop(base::Bind(&base::DoNothing));
 }
 
+void ScreenCaptureDeviceCore::OnConsumerReportingUtilization(
+    int frame_id,
+    double utilization) {
+  oracle_proxy_->OnConsumerReportingUtilization(frame_id, utilization);

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

Could |oracle_proxy_| be null here? Not sure whether to:

1. DCHECK(oracle_proxy_);

or

2. if (state != kCapturing && state_ != kSuspended)
     return;

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

Thanks for raising this.
This makes me realize that it is not a good idea to have this method be called
from threads other than the other methods (probably the "device thread"). I now
made changes to the factory logic in VideoCaptureManager and
VideoCaptureController to ensure that consumer utilization is always reported on
the device thread.

With this change, it should be guaranteed that no utilization reports arrive
after StopAndDeAllicate has been called. Therefore, I am going to opt for a
DCHECK.

+}
+
 void ScreenCaptureDeviceCore::CaptureStarted(bool success) {
   DCHECK(thread_checker_.CalledOnValidThread());
   if (!success)