Set |_encodedWidth| and |_encodedHeight| in RtpFrameObject.

BUG=chromium:678080

Review-Url: https://codereview.webrtc.org/2622053003
Cr-Commit-Position: refs/heads/master@{#16029}
diff --git a/webrtc/modules/video_coding/frame_object.cc b/webrtc/modules/video_coding/frame_object.cc
index 0dd06ab..d593d4b 100644
--- a/webrtc/modules/video_coding/frame_object.cc
+++ b/webrtc/modules/video_coding/frame_object.cc
@@ -63,6 +63,8 @@
   _length = frame_size;
   _frameType = first_packet->frameType;
   GetBitstream(_buffer);
+  _encodedWidth = first_packet->width;
+  _encodedHeight = first_packet->height;
 
   // FrameObject members
   timestamp = first_packet->timestamp;