Drop dependency on webrtc's tick_utils.h.

content/renderer/media/webrtc/media_stream_remote_video_source.cc

 // Copyright 2014 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.
 
 #include "content/renderer/media/webrtc/media_stream_remote_video_source.h"
 
 #include <stdint.h>
 #include <utility>
 
 #include "base/bind.h"
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/threading/thread_checker.h"
 #include "base/trace_event/trace_event.h"
 #include "content/renderer/media/webrtc/track_observer.h"
 #include "media/base/bind_to_current_loop.h"
 #include "media/base/timestamp_constants.h"
 #include "media/base/video_frame.h"
 #include "media/base/video_util.h"
 #include "third_party/webrtc/media/base/videoframe.h"
 #include "third_party/webrtc/media/base/videosinkinterface.h"
-#include "third_party/webrtc/system_wrappers/include/tick_util.h"
 
 namespace content {
 
 // Internal class used for receiving frames from the webrtc track on a
 // libjingle thread and forward it to the IO-thread.
 class MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate
     : public base::RefCountedThreadSafe<RemoteVideoSourceDelegate>,
       public rtc::VideoSinkInterface<cricket::VideoFrame> {
  public:
   RemoteVideoSourceDelegate(
@@ skipping 30 matching lines @@
 MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::
     RemoteVideoSourceDelegate(
         scoped_refptr<base::SingleThreadTaskRunner> io_task_runner,
         const VideoCaptureDeliverFrameCB& new_frame_callback)
     : io_task_runner_(io_task_runner),
       frame_callback_(new_frame_callback),
       start_timestamp_(media::kNoTimestamp()),
       // 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_(base::TimeTicks::Now() - base::TimeTicks() -

[perkj_webrtc, 2016/04/14 13:46:23]

Isn't all these methods from the same clock in the same base?  ie- Isn't this
always 0? 

[nisse-webrtc, 2016/04/19 11:12:41]

I haven't yet tried to understand time sources in chrome. Hopefully they're all
clock_gettime(CLOCK_MONOTONIC), or some analogous clock on non-posix systems.

time_diff_ was added in cl https://codereview.chromium.org/1320183003, it seems.

-                 base::TimeDelta::FromMicroseconds(
-                     webrtc::TickTime::MicrosecondTimestamp())) {}
+                 base::TimeDelta::FromMicroseconds(rtc::TimeMicros())) {}
 
 MediaStreamRemoteVideoSource::
 RemoteVideoSourceDelegate::~RemoteVideoSourceDelegate() {
 }
 
 void MediaStreamRemoteVideoSource::RemoteVideoSourceDelegate::OnFrame(
     const cricket::VideoFrame& incoming_frame) {
   const base::TimeDelta incoming_timestamp = base::TimeDelta::FromMicroseconds(
       incoming_frame.GetTimeStamp() / rtc::kNumNanosecsPerMicrosec);
   const base::TimeTicks render_time =
@@ skipping 128 matching lines @@
     case webrtc::MediaStreamTrackInterface::kEnded:
       SetReadyState(blink::WebMediaStreamSource::ReadyStateEnded);
       break;
     default:
       NOTREACHED();
       break;
   }
 }
 
 }  // namespace content