RESOURCE_UTILIZATION in VideoFrameMetadata, a consumer feedback signal.

content/browser/media/capture/content_video_capture_device_core.cc

Index: content/browser/media/capture/content_video_capture_device_core.cc
diff --git a/content/browser/media/capture/content_video_capture_device_core.cc b/content/browser/media/capture/content_video_capture_device_core.cc
index b4bb853a5acac92a99a385fe1d111844fb16cd73..23c0c02336077c47c1ea8b1c7b89fb22170c7fc6 100644
--- a/content/browser/media/capture/content_video_capture_device_core.cc
+++ b/content/browser/media/capture/content_video_capture_device_core.cc
@@ -22,7 +22,6 @@
 #include "base/time/time.h"
 #include "base/trace_event/trace_event.h"
 #include "content/public/browser/browser_thread.h"
-#include "media/base/bind_to_current_loop.h"
 #include "media/base/video_capture_types.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_frame_metadata.h"
@@ -192,11 +191,35 @@ void ThreadSafeCaptureOracle::DidCaptureFrame(
           media::VideoFrameMetadata::CAPTURE_END_TIME, base::TimeTicks::Now());
       frame->metadata()->SetTimeDelta(media::VideoFrameMetadata::FRAME_DURATION,
                                       estimated_frame_duration);
+
+      frame->AddDestructionObserver(base::Bind(
+          &ThreadSafeCaptureOracle::DidConsumeFrame,
+          this,
+          frame_number,
+          frame->metadata()));
+
       client_->OnIncomingCapturedVideoFrame(buffer.Pass(), frame, timestamp);
     }
   }
 }
 
+void ThreadSafeCaptureOracle::DidConsumeFrame(
+    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 stress_level = -1.0;
+  if (metadata->GetDouble(media::VideoFrameMetadata::STRESS_LEVEL,
+                          &stress_level) &&
+      stress_level >= 0.0) {
+    VLOG(2) << "Consumer stress level for frame " << frame_number
+            << ": " << stress_level;
+  }
+
+  // TODO(miu): Use |stress_level| to drive automatic video resolution changes.
+  // http://crbug.com/156767.
+}
+
 void ContentVideoCaptureDeviceCore::AllocateAndStart(
     const media::VideoCaptureParams& params,
     scoped_ptr<media::VideoCaptureDevice::Client> client) {