Run VDA::Decode on GPU IO thread if VDA supports it.

content/common/gpu/media/video_decode_accelerator_impl.h

+// Copyright (c) 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 CONTENT_COMMON_GPU_MEDIA_VIDEO_DECODE_ACCELERATOR_IMPL_H_
+#define CONTENT_COMMON_GPU_MEDIA_VIDEO_DECODE_ACCELERATOR_IMPL_H_
+
+#include "content/common/content_export.h"
+#include "media/video/video_decode_accelerator.h"
+
+namespace content {
+
+class CONTENT_EXPORT VideoDecodeAcceleratorImpl
+    : public media::VideoDecodeAccelerator {
+ public:
+  VideoDecodeAcceleratorImpl();
+  virtual ~VideoDecodeAcceleratorImpl();
+
+  // Returns true if media::VideoDecodeAccelerator::Decode can run on the IO
+  // thread. Otherwise Decode will run on the GPU child thread. The purpose of
+  // running Decode on the IO thread is to reduce decode latency. Note Decode
+  // should return as soon as possible and not block on the IO thread.
+  virtual bool CanDecodeOnIOThread();
+};
+
+}  // namespace content
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VIDEO_DECODE_ACCELERATOR_IMPL_H_