Cast: Fix threading issues in VideoEncoderImpl

media/cast/video_sender/codecs/vp8/vp8_encoder.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_CAST_VIDEO_SENDER_CODECS_VP8_VP8_ENCODER_H_
 #define MEDIA_CAST_VIDEO_SENDER_CODECS_VP8_VP8_ENCODER_H_
 
 #include "base/basictypes.h"
 #include "base/memory/scoped_ptr.h"
+#include "base/threading/thread_checker.h"
 #include "media/cast/cast_config.h"
 #include "third_party/libvpx/source/libvpx/vpx/vpx_encoder.h"
 
 namespace media {
 class VideoFrame;
 }
 
 // VPX forward declaration.
 typedef struct vpx_codec_ctx vpx_enc_ctx_t;
 
 namespace media {
 namespace cast {
 
 const int kNumberOfVp8VideoBuffers = 3;
 
 class Vp8Encoder {
  public:
   Vp8Encoder(const VideoSenderConfig& video_config,
              uint8 max_unacked_frames);
 
   ~Vp8Encoder();
 
+  // Initialize the encoder before Encode() can be called. This method
+  // must be called on the thread that Encode() is called.
+  void Initialize();
+
   // Encode a raw image (as a part of a video stream).
   bool Encode(const scoped_refptr<media::VideoFrame>& video_frame,
               transport::EncodedVideoFrame* encoded_image);
 
   // Update the encoder with a new target bit rate.
   void UpdateRates(uint32 new_bitrate);
 
   // Set the next frame to be a key frame.
   void GenerateKeyFrame();
 
@@ skipping 34 matching lines @@
   scoped_ptr<vpx_enc_ctx_t> encoder_;
   vpx_image_t* raw_image_;
 
   bool key_frame_requested_;
   int64 timestamp_;
   uint32 last_encoded_frame_id_;
   uint32 used_buffers_frame_id_[kNumberOfVp8VideoBuffers];
   bool acked_frame_buffers_[kNumberOfVp8VideoBuffers];
   Vp8Buffers last_used_vp8_buffer_;
   int number_of_repeated_buffers_;
+
+  // This is bound to the thread where Initialize() is called.
+  base::ThreadChecker thread_checker_;
 };
 
 }  // namespace cast
 }  // namespace media
 
 #endif  // MEDIA_CAST_VIDEO_SENDER_CODECS_VP8_VP8_ENCODER_H_