Move the DXVA decoder off the GPU thread.

content/common/gpu/media/dxva_video_decode_accelerator.h

Index: content/common/gpu/media/dxva_video_decode_accelerator.h
diff --git a/content/common/gpu/media/dxva_video_decode_accelerator.h b/content/common/gpu/media/dxva_video_decode_accelerator.h
index c544cf67e4e4dabda5f4b9de532369f5262ed67c..939d6953120b01c15d02db3b3edfdd893a4430a0 100644
--- a/content/common/gpu/media/dxva_video_decode_accelerator.h
+++ b/content/common/gpu/media/dxva_video_decode_accelerator.h
@@ -21,6 +21,7 @@
 #include "base/memory/linked_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/threading/non_thread_safe.h"
+#include "base/threading/thread.h"
 #include "base/win/scoped_comptr.h"
 #include "content/common/content_export.h"
 #include "media/video/video_decode_accelerator.h"
@@ -68,6 +69,10 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
  private:
   typedef void* EGLConfig;
   typedef void* EGLSurface;
+  // List of input samples waiting to be processed.
+  typedef std::list<base::win::ScopedComPtr<IMFSample>> PendingInputs;
+  PendingInputs pending_input_buffers_;

[DaleCurtis, 2014/12/03 01:04:33]

This should be declared below and the typedef with the Notify method.

+
   // Creates and initializes an instance of the D3D device and the
   // corresponding device manager. The device manager instance is eventually
   // passed to the IMFTransform interface implemented by the decoder.
@@ -135,7 +140,7 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
 
   // Sends pending input buffer processed acks to the client if we don't have
   // output samples waiting to be processed.
-  void NotifyInputBuffersDropped();
+  void NotifyInputBuffersDropped(const PendingInputs& input_buffers);
 
   // Decodes pending input buffers.
   void DecodePendingInputBuffers();
@@ -158,6 +163,18 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   // Called after the client indicates we can recycle a stale picture buffer.
   void DeferredDismissStaleBuffer(int32 picture_buffer_id);
 
+  // Sets the state of the decoder. Can be called from the main thread and
+  // the decoder thread. Threadsafe.

[DaleCurtis, 2014/12/03 01:04:33]

"thread-safe" or "thread safe" -- up to you.

[ananta, 2014/12/03 04:08:02]

Reworded

+  void SetState(State state);
+
+  // Gets the state of the decoder. Can be called from the main thread and
+  // the decoder thread. Threadsafe.
+  State GetState() const;
+
+  // Worker function for the Decoder Reset functionality. Executes on the
+  // decoder thread and queues tasks on the main thread as needed.
+  void ResetHelper();
+
   // To expose client callbacks from VideoDecodeAccelerator.
   media::VideoDecodeAccelerator::Client* client_;
 
@@ -214,10 +231,6 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   // decode.
   int inputs_before_decode_;
 
-  // List of input samples waiting to be processed.
-  typedef std::list<base::win::ScopedComPtr<IMFSample>> PendingInputs;
-  PendingInputs pending_input_buffers_;
-
   // Callback to set the correct gl context.
   base::Callback<bool(void)> make_context_current_;
 
@@ -226,6 +239,16 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
 
   // Which codec we are decoding with hardware acceleration.
   media::VideoCodec codec_;
+  // Thread on which the decoder operations like passing input frames,
+  // getting output frames are performed. One instance of this thread
+  // is created per decoder instance.
+  base::Thread decoder_thread_;
+
+  // Task runner to be used for posting tasks to the decoder thread.
+  scoped_refptr<base::TaskRunner> decoder_thread_task_runner_;
+
+  // Task runner to be used for posting tasks to the main thread.
+  scoped_refptr<base::TaskRunner> main_thread_task_runner_;
 };
 
 }  // namespace content