Cast: Forcing codec initialization on a designated thread

media/cast/video_receiver/codecs/vp8/vp8_decoder.cc

Index: media/cast/video_receiver/codecs/vp8/vp8_decoder.cc
diff --git a/media/cast/video_receiver/codecs/vp8/vp8_decoder.cc b/media/cast/video_receiver/codecs/vp8/vp8_decoder.cc
index bf56b0a2ad11896d851fd498b95e18de54fe8883..ecb7e63249b58d876cc47dd5976af51f2b464793 100644
--- a/media/cast/video_receiver/codecs/vp8/vp8_decoder.cc
+++ b/media/cast/video_receiver/codecs/vp8/vp8_decoder.cc
@@ -19,18 +19,20 @@ void LogFrameDecodedEvent(CastEnvironment* const cast_environment,
 //      0, frame_id);
 }
 
-Vp8Decoder::Vp8Decoder(int number_of_cores,
-                       scoped_refptr<CastEnvironment> cast_environment)
+Vp8Decoder::Vp8Decoder(scoped_refptr<CastEnvironment> cast_environment)
     : decoder_(new vpx_dec_ctx_t()),
       cast_environment_(cast_environment) {
-  InitDecode(number_of_cores);
+  // Make sure that we initialize the decoder from the correct thread.
+  cast_environment_->PostTask(CastEnvironment::VIDEO_DECODER, FROM_HERE,
+        base::Bind(&Vp8Decoder::InitDecoder, base::Unretained(this)));
 }
 
 Vp8Decoder::~Vp8Decoder() {}
 
-void Vp8Decoder::InitDecode(int number_of_cores) {
-  vpx_codec_dec_cfg_t  cfg;
-  cfg.threads = number_of_cores;
+void Vp8Decoder::InitDecoder() {
+  vpx_codec_dec_cfg_t cfg;
+  // Initializing to use one core.
+  cfg.threads = 1;
   vpx_codec_flags_t flags = VPX_CODEC_USE_POSTPROC;
 
   if (vpx_codec_dec_init(decoder_.get(), vpx_codec_vp8_dx(), &cfg, flags)) {
@@ -41,6 +43,7 @@ void Vp8Decoder::InitDecode(int number_of_cores) {
 bool Vp8Decoder::Decode(const EncodedVideoFrame* encoded_frame,
                         const base::TimeTicks render_time,
                         const VideoFrameDecodedCallback& frame_decoded_cb) {
+  DCHECK(cast_environment_->CurrentlyOn(CastEnvironment::VIDEO_DECODER));
   const int frame_id_int = static_cast<int>(encoded_frame->frame_id);
   VLOG(1) << "VP8 decode frame:" << frame_id_int
           << " sized:" << encoded_frame->data.size();
@@ -94,8 +97,8 @@ bool Vp8Decoder::Decode(const EncodedVideoFrame* encoded_frame,
   // Log:: Decoding complete (should be called from the main thread).
   cast_environment_->PostTask(CastEnvironment::MAIN, FROM_HERE, base::Bind(
       LogFrameDecodedEvent, cast_environment_,encoded_frame->frame_id));
-  VLOG(1) << "Decoded frame " << frame_id_int;
 
+  VLOG(1) << "Decoded frame " << frame_id_int;
   // Frame decoded - return frame to the user via callback.
   cast_environment_->PostTask(CastEnvironment::MAIN, FROM_HERE,
       base::Bind(frame_decoded_cb, base::Passed(&decoded_frame),