Use NTP time for video frame timestamp. Add tracing for timestamps.

content/browser/renderer_host/media/web_contents_video_capture_device.cc

 // Copyright (c) 2012 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.
 //
 // Implementation notes: This needs to work on a variety of hardware
 // configurations where the speed of the CPU and GPU greatly affect overall
 // performance. Spanning several threads, the process of capturing has been
 // split up into four conceptual stages:
 //
 //   1. Reserve Buffer: Before a frame can be captured, a slot in the consumer's
@@ skipping 499 matching lines @@
   is_started_ = false;
   consumer_ = NULL;
 }
 
 void CaptureOracle::DidCaptureFrame(
     const scoped_refptr<media::VideoFrame>& frame,
     base::Time timestamp,
     bool success) {
   base::AutoLock guard(lock_);
 
-  TRACE_EVENT_ASYNC_END1("mirroring", "Capture", frame.get(),
-                         "success", success);
+  TRACE_EVENT_ASYNC_END2("mirroring", "Capture", frame.get(),
+                         "success", success,
+                         "timestamp", timestamp.ToInternalValue());
 
   if (!consumer_ || !is_started_)
     return;  // Capture is stopped.
 
   if (success)
     consumer_->OnIncomingCapturedVideoFrame(frame, timestamp);
 }
 
 bool FrameSubscriber::ShouldCaptureFrame(
     scoped_refptr<media::VideoFrame>* storage,
@@ skipping 766 matching lines @@
     return false;
   else
     return true;
 }
 
 base::Time SmoothEventSampler::GetLastSampledEvent() {
   return last_sample_;
 }
 
 }  // namespace content