Wire up bandwidth limitation info to GetStats and adapt_reason.

talk/media/webrtc/webrtcvideoengine2.cc

Index: talk/media/webrtc/webrtcvideoengine2.cc
diff --git a/talk/media/webrtc/webrtcvideoengine2.cc b/talk/media/webrtc/webrtcvideoengine2.cc
index 6b699fe4fb277adb278f8e0ad1b1b4ffff99f620..7593a0cd5562a84c40d222f7666410a5b3a1b1b2 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -2194,6 +2194,14 @@ WebRtcVideoChannel2::WebRtcVideoSendStream::GetVideoSenderInfo() {
       }
     }
   }
+
+  // Get bandwidth limitation info from stream_->GetStats().
+  // Input resolution (output from video_adapter) can be further scaled down or
+  // higher video layer(s) can be dropped due to bitrate constraints.
+  // Note, adapt_changes only include changes from the video_adapter.
+  if (stats.bw_limited_resolution)
+    info.adapt_reason |= CoordinatedVideoAdapter::ADAPTREASON_BANDWIDTH;
+
   info.ssrc_groups = ssrc_groups_;
   info.framerate_input = stats.input_frame_rate;
   info.framerate_sent = stats.encode_frame_rate;