Implement timing frames.

webrtc/common_video/include/video_frame.h

Index: webrtc/common_video/include/video_frame.h
diff --git a/webrtc/common_video/include/video_frame.h b/webrtc/common_video/include/video_frame.h
index 1e8f37c171c7cf4bdb850d7665d4c084a69155d3..7f0b13ca755ec42ca51763ab0874131a6160fcf9 100644
--- a/webrtc/common_video/include/video_frame.h
+++ b/webrtc/common_video/include/video_frame.h
@@ -63,6 +63,17 @@ class EncodedImage {
   // indication that all future frames will be constrained with those limits
   // until the application indicates a change again.
   PlayoutDelay playout_delay_ = {-1, -1};
+
+  struct Timing {
+    bool is_timing_frame = false;
+    int64_t encode_start_ms = 0;
+    int64_t encode_finish_ms = 0;
+    int64_t packetization_finish_ms = 0;
+    int64_t pacer_exit_ms = 0;
+    int64_t network_timestamp_ms = 0;
+    int64_t receive_start_ms = 0;
+    int64_t receive_finish_ms = 0;
+  } timing_;
 };
 
 }  // namespace webrtc