Pass the encoder's internal source property through to video_sender to request a keyframe from the e

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 3fd5690125ad8d2cb3fd954fdc00e8c2c742742e..5f4edf66e32217fe5c3a09eda453399f389a976d 100644
--- a/talk/media/webrtc/webrtcvideoengine2.cc
+++ b/talk/media/webrtc/webrtcvideoengine2.cc
@@ -1947,6 +1947,11 @@ void WebRtcVideoChannel2::WebRtcVideoSendStream::SetCodecAndOptions(
   parameters_.config.encoder_settings.encoder = new_encoder.encoder;
   parameters_.config.encoder_settings.payload_name = codec_settings.codec.name;
   parameters_.config.encoder_settings.payload_type = codec_settings.codec.id;
+  if (new_encoder.external) {
+    webrtc::VideoCodecType type = CodecTypeFromName(codec_settings.codec.name);
+    parameters_.config.encoder_settings.internal_source =
+        external_encoder_factory_->EncoderTypeHasInternalSource(type);
+  }
   parameters_.config.rtp.fec = codec_settings.fec;
 
   // Set RTX payload type if RTX is enabled.