Move responsibility for RTP header extensions on video receive.

webrtc/pc/webrtcsession.cc

Index: webrtc/pc/webrtcsession.cc
diff --git a/webrtc/pc/webrtcsession.cc b/webrtc/pc/webrtcsession.cc
index c6046e905fd48e3a57b98315d49bebe091b56dfd..93a92ef20d98783bb28b7b0ca7e805d719a4cb02 100644
--- a/webrtc/pc/webrtcsession.cc
+++ b/webrtc/pc/webrtcsession.cc
@@ -950,6 +950,16 @@ bool WebRtcSession::PushdownMediaDescription(
     if (!ch) {
       return true;
     } else if (source == cricket::CS_LOCAL) {
+      const SessionDescription* local_desc = local_description()->description();
+      const ContentInfo* content_info = GetFirstDataContent(local_desc);
+      RTC_DCHECK(IsVideoContent(content_info));
+      const cricket::VideoContentDescription* content_desc =
+          static_cast<const cricket::VideoContentDescription*>(
+              content_info->description);
+      if (content_desc->rtp_header_extensions_set())
+        media_controller_->SetVideoReceiveRtpHeaderExtensions(
+            content_desc->rtp_header_extensions());
+
       return ch->PushdownLocalDescription(local_description()->description(),
                                           action, err);
     } else {