Cast:Forcing VP8 codec initialization on a designated thread.

Makes sure that all interaction with the video decoder is done on the VIDEO_DECODER thread.
Logging which was removed here, will be added in a follow  up cl.

Review URL: https://codereview.chromium.org/80383006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238535 0039d316-1c4b-4281-b951-d872f2087c98

media/cast/test/encode_decode_test.cc

@@ -90,7 +90,7 @@ class EncodeDecodeTest : public ::testing::Test {
     int max_unacked_frames = 1;
     encoder_.reset(new Vp8Encoder(encoder_config_, max_unacked_frames));
     // Initialize to use one core.
-    decoder_.reset(new Vp8Decoder(1, cast_environment_));
+    decoder_.reset(new Vp8Decoder(cast_environment_));
   }
 
   virtual ~EncodeDecodeTest() {}

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) {
+void Vp8Decoder::InitDecoder() {
   vpx_codec_dec_cfg_t cfg;
-  cfg.threads = number_of_cores;
+  // 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),

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

@@ -21,8 +21,7 @@ namespace cast {
 // thread.
 class Vp8Decoder : public base::NonThreadSafe {
  public:
-  Vp8Decoder(int number_of_cores,
-             scoped_refptr<CastEnvironment> cast_environment);
+  explicit Vp8Decoder(scoped_refptr<CastEnvironment> cast_environment);
   ~Vp8Decoder();
 
   // Decode frame - The decoded frame will be passed via the callback.
@@ -35,8 +34,7 @@ class Vp8Decoder : public base::NonThreadSafe {
 
  private:
   // Initialize the decoder.
-  void InitDecode(int number_of_cores);
-
+  void InitDecoder();
   scoped_ptr<vpx_dec_ctx_t> decoder_;
   scoped_refptr<CastEnvironment> cast_environment_;
 };

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();