Change default timestamp to 64 bits in all webrtc directories.

webrtc/media/engine/webrtcvideoengine2.cc

Index: webrtc/media/engine/webrtcvideoengine2.cc
diff --git a/webrtc/media/engine/webrtcvideoengine2.cc b/webrtc/media/engine/webrtcvideoengine2.cc
index 383f29a9228250f4ab9fa171802e1da8f586ca19..785ec692e6a26147f476da8810fb96c419b8cbf1 100644
--- a/webrtc/media/engine/webrtcvideoengine2.cc
+++ b/webrtc/media/engine/webrtcvideoengine2.cc
@@ -1591,7 +1591,7 @@ void WebRtcVideoChannel2::WebRtcVideoSendStream::OnFrame(
   // frame->GetTimeStamp() is essentially a delta, align to webrtc time
   if (!first_frame_timestamp_ms_) {
     first_frame_timestamp_ms_ =
-        rtc::Optional<int64_t>(rtc::Time() - frame_delta_ms);
+        rtc::Optional<int64_t>(rtc::TimeMillis() - frame_delta_ms);
   }
 
   last_frame_timestamp_ms_ = *first_frame_timestamp_ms_ + frame_delta_ms;