Revert of Remove SendPacer from ViEEncoder

webrtc/video/vie_encoder.h

Index: webrtc/video/vie_encoder.h
diff --git a/webrtc/video/vie_encoder.h b/webrtc/video/vie_encoder.h
index 5f033aaef17064285f50fc225126e80833c0e0eb..3d05a157e7e039de0f7535a01e34cea69e871d2b 100644
--- a/webrtc/video/vie_encoder.h
+++ b/webrtc/video/vie_encoder.h
@@ -61,7 +61,10 @@
              const std::vector<uint32_t>& ssrcs,
              ProcessThread* module_process_thread,
              SendStatisticsProxy* stats_proxy,
-             OveruseFrameDetector* overuse_detector);
+             // TODO(nisse): Used only for tests, delete?
+             rtc::VideoSinkInterface<VideoFrame>* pre_encode_callback,
+             OveruseFrameDetector* overuse_detector,
+             PacedSender* pacer);
   ~ViEEncoder();
 
   bool Init();
@@ -140,7 +143,9 @@
   rtc::CriticalSection data_cs_;
 
   SendStatisticsProxy* const stats_proxy_;
+  rtc::VideoSinkInterface<VideoFrame>* const pre_encode_callback_;
   OveruseFrameDetector* const overuse_detector_;
+  PacedSender* const pacer_;
 
   // The time we last received an input frame or encoded frame. This is used to
   // track when video is stopped long enough that we also want to stop sending