Revert of Delete cricket::VideoFrame::GetTimeStamp.

webrtc/sdk/objc/Framework/Classes/RTCVideoRendererAdapter.mm

 /*
  *  Copyright 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 12 matching lines @@
  public:
   VideoRendererAdapter(RTCVideoRendererAdapter* adapter) {
     adapter_ = adapter;
     size_ = CGSizeZero;
   }
 
   void OnFrame(const cricket::VideoFrame& nativeVideoFrame) override {
     RTCVideoFrame* videoFrame = [[RTCVideoFrame alloc]
         initWithVideoBuffer:nativeVideoFrame.video_frame_buffer()
                    rotation:nativeVideoFrame.rotation()
-                timeStampNs:nativeVideoFrame.timestamp_us() *
-                                rtc::kNumNanosecsPerMicrosec];
+                timeStampNs:nativeVideoFrame.GetTimeStamp()];
     CGSize current_size = (videoFrame.rotation % 180 == 0)
                               ? CGSizeMake(videoFrame.width, videoFrame.height)
                               : CGSizeMake(videoFrame.height, videoFrame.width);
 
     if (!CGSizeEqualToSize(size_, current_size)) {
       size_ = current_size;
       [adapter_.videoRenderer setSize:size_];
     }
     [adapter_.videoRenderer renderFrame:videoFrame];
   }
@@ skipping 17 matching lines @@
     _adapter.reset(new webrtc::VideoRendererAdapter(self));
   }
   return self;
 }
 
 - (rtc::VideoSinkInterface<cricket::VideoFrame> *)nativeVideoRenderer {
   return _adapter.get();
 }
 
 @end