Add video timing frames to set of default RTP header extensions

webrtc/media/engine/webrtcvideoengine.cc

Index: webrtc/media/engine/webrtcvideoengine.cc
diff --git a/webrtc/media/engine/webrtcvideoengine.cc b/webrtc/media/engine/webrtcvideoengine.cc
index 2ff5f08b4d1e514d9cb641873d3a4b0aff74d260..24da3c2328f8b6223c7dad2932e734560f26f3d2 100644
--- a/webrtc/media/engine/webrtcvideoengine.cc
+++ b/webrtc/media/engine/webrtcvideoengine.cc
@@ -426,8 +426,9 @@ RtpCapabilities WebRtcVideoEngine::GetCapabilities() const {
   capabilities.header_extensions.push_back(
       webrtc::RtpExtension(webrtc::RtpExtension::kVideoContentTypeUri,
                            webrtc::RtpExtension::kVideoContentTypeDefaultId));
-  // TODO(ilnik): Add kVideoTimingUri/kVideoTimingDefaultId to capabilities.
-  // Possibly inside field trial.
+  capabilities.header_extensions.push_back(
+        webrtc::RtpExtension(webrtc::RtpExtension::kVideoTimingUri,
+                             webrtc::RtpExtension::kVideoTimingDefaultId));
   return capabilities;
 }