Preliminary change for new rtc rendering algorithm

content/renderer/media/webrtc/media_stream_remote_video_source.cc

Index: content/renderer/media/webrtc/media_stream_remote_video_source.cc
diff --git a/content/renderer/media/webrtc/media_stream_remote_video_source.cc b/content/renderer/media/webrtc/media_stream_remote_video_source.cc
index e81b37701de15df10019bdf517c105cdc50cffef..e325f797f6dee470e8e9c5c5b84e194b5d43716d 100644
--- a/content/renderer/media/webrtc/media_stream_remote_video_source.cc
+++ b/content/renderer/media/webrtc/media_stream_remote_video_source.cc
@@ -14,6 +14,7 @@
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 #include "third_party/libjingle/source/talk/media/base/videoframe.h"
+#include "third_party/webrtc/system_wrappers/interface/tick_util.h"
 
 namespace content {
 
@@ -47,6 +48,9 @@ class MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate
 
   // |frame_callback_| is accessed on the IO thread.
   VideoCaptureDeliverFrameCB frame_callback_;
+
+  // WebRTC Chromium timestamp diff
+  int64_t time_diff_us_;
 };
 
 MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::
@@ -54,6 +58,12 @@ MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::
         scoped_refptr<base::SingleThreadTaskRunner> io_task_runner,
         const VideoCaptureDeliverFrameCB& new_frame_callback)
     : io_task_runner_(io_task_runner), frame_callback_(new_frame_callback) {
+  // TODO(qiangchen): There can be two differences between clocks: 1)
+  // the offset, 2) the rate (i.e., one clock runs faster than the other).
+  // See http://crbug/516700
+  time_diff_us_ =
+      (base::TimeTicks::Now() - base::TimeTicks()).InMicroseconds() -
+      webrtc::TickTime::MicrosecondTimestamp();
 }
 
 MediaStreamRemoteVideoSource::
@@ -62,7 +72,14 @@ RemoteVideoSourceDelegate::~RemoteVideoSourceDelegate() {
 
 void MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::RenderFrame(
     const cricket::VideoFrame* incoming_frame) {
-  TRACE_EVENT0("webrtc", "RemoteVideoSourceDelegate::RenderFrame");
+  base::TimeTicks render_time =
+      base::TimeTicks() +
+      base::TimeDelta::FromMicroseconds(incoming_frame->GetTimeStamp() / 1000 +
+                                        time_diff_us_);
+
+  TRACE_EVENT1("webrtc", "RemoteVideoSourceDelegate::RenderFrame",
+               "Ideal Render Instant", render_time.ToInternalValue());
+
   base::TimeDelta timestamp = base::TimeDelta::FromMicroseconds(
       incoming_frame->GetElapsedTime() / rtc::kNumNanosecsPerMicrosec);
 
@@ -96,6 +113,9 @@ void MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::RenderFrame(
         base::Bind(&base::DeletePointer<cricket::VideoFrame>, frame->Copy()));
   }
 
+  video_frame->metadata()->SetTimeTicks(
+      media::VideoFrameMetadata::REFERENCE_TIME, render_time);
+
   io_task_runner_->PostTask(
       FROM_HERE, base::Bind(&RemoteVideoSourceDelegate::DoRenderFrameOnIOThread,
                             this, video_frame));