Cast: Forcing codec initialization on a designated thread

media/cast/video_receiver/video_decoder.cc

Index: media/cast/video_receiver/video_decoder.cc
diff --git a/media/cast/video_receiver/video_decoder.cc b/media/cast/video_receiver/video_decoder.cc
index 03f7a25d44bcf869de63c904a117f93768bd2f44..e4d473866d1a932f428174ae91a3103728ff2725 100644
--- a/media/cast/video_receiver/video_decoder.cc
+++ b/media/cast/video_receiver/video_decoder.cc
@@ -18,8 +18,7 @@ VideoDecoder::VideoDecoder(const VideoReceiverConfig& video_config,
       vp8_decoder_() {
   switch (video_config.codec) {
     case kVp8:
-      // Initializing to use one core.
-      vp8_decoder_.reset(new Vp8Decoder(1, cast_environment));
+      vp8_decoder_.reset(new Vp8Decoder(cast_environment));
       break;
     case kH264:
       NOTIMPLEMENTED();
@@ -32,6 +31,11 @@ VideoDecoder::VideoDecoder(const VideoReceiverConfig& video_config,
 
 VideoDecoder::~VideoDecoder() {}
 
+void VideoDecoder::InitDecoder() {
+  // Initializing to use one core.
+  vp8_decoder_->InitDecoder();
+}
+
 bool VideoDecoder::DecodeVideoFrame(const EncodedVideoFrame* encoded_frame,
                                     const base::TimeTicks render_time,
                                     const VideoFrameDecodedCallback&