RESOURCE_UTILIZATION in VideoFrameMetadata, a consumer feedback signal.

content/browser/renderer_host/media/video_capture_controller.cc

Index: content/browser/renderer_host/media/video_capture_controller.cc
diff --git a/content/browser/renderer_host/media/video_capture_controller.cc b/content/browser/renderer_host/media/video_capture_controller.cc
index 23ee7074a2d73a365000d5369b39d28e50b2adc8..10411fcc8468e18cb2df9cee9295708529503e9c 100644
--- a/content/browser/renderer_host/media/video_capture_controller.cc
+++ b/content/browser/renderer_host/media/video_capture_controller.cc
@@ -28,6 +28,7 @@
 
 using media::VideoCaptureFormat;
 using media::VideoFrame;
+using media::VideoFrameMetadata;
 
 namespace content {
 
@@ -234,7 +235,8 @@ void VideoCaptureController::ReturnBuffer(
     VideoCaptureControllerID id,
     VideoCaptureControllerEventHandler* event_handler,
     int buffer_id,
-    uint32 sync_point) {
+    uint32 sync_point,
+    double consumer_stress_level) {
   DCHECK_CURRENTLY_ON(BrowserThread::IO);
 
   ControllerClient* client = FindClient(id, event_handler, controller_clients_);
@@ -247,7 +249,24 @@ void VideoCaptureController::ReturnBuffer(
     NOTREACHED();
     return;
   }
+
+  // Set the STRESS_LEVEL to the maximum of those provided by each consumer.  A
+  // producer of the VideoFrame may check this value to make quality versus
+  // performance trade-off decisions.
   scoped_refptr<VideoFrame> frame = iter->second;
+  if (std::isfinite(consumer_stress_level) && consumer_stress_level >= 0.0) {
+    double stress_level = -1.0;
+    if (frame->metadata()->GetDouble(VideoFrameMetadata::STRESS_LEVEL,
+                                     &stress_level)) {
+      frame->metadata()->SetDouble(VideoFrameMetadata::STRESS_LEVEL,
+                                   std::max(consumer_stress_level,
+                                            stress_level));
+    } else {
+      frame->metadata()->SetDouble(VideoFrameMetadata::STRESS_LEVEL,
+                                   consumer_stress_level);
+    }
+  }
+
   client->active_buffers.erase(iter);
   buffer_pool_->RelinquishConsumerHold(buffer_id, 1);