Measure encoding time on encode callbacks.

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 6f04d9674a15d7fb83afbf80b2e57483fbc2d626..3567b98a9fa9346675336ad92ac608cde8321985 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -1768,6 +1768,7 @@ void WebRtcVideoChannel2::WebRtcVideoSendStream::SetCodecAndOptions(
 
   AllocatedEncoder new_encoder = CreateVideoEncoder(codec_settings.codec);
   parameters_.config.encoder_settings.encoder = new_encoder.encoder;
+  parameters_.config.encoder_settings.full_overuse_time = new_encoder.external;
   parameters_.config.encoder_settings.payload_name = codec_settings.codec.name;
   parameters_.config.encoder_settings.payload_type = codec_settings.codec.id;
   if (new_encoder.external) {