Merge VideoDecodeAcceleratorImpl with VideoDecodeAccelerator

media/video/video_decode_accelerator.h

Index: media/video/video_decode_accelerator.h
diff --git a/media/video/video_decode_accelerator.h b/media/video/video_decode_accelerator.h
index 7025a51cc82ae5db83b9befcc17fb0284005e5ff..4df3b1c915836ef4dee55690d6a6880c3d1b24de 100644
--- a/media/video/video_decode_accelerator.h
+++ b/media/video/video_decode_accelerator.h
@@ -132,6 +132,17 @@ class MEDIA_EXPORT VideoDecodeAccelerator {
   // unconditionally, so make sure to drop all pointers to it!
   virtual void Destroy() = 0;
 
+  // GPU PROCESS ONLY.  Implementations of this interface in the
+  // content/common/gpu/media should implement this, and implementations in
+  // other processes should not override the default implementation.
+  // Returns true if VDA::Decode and VDA::Client callbacks can run on the IO
+  // thread. Otherwise they 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. Also,
+  // PictureReady should be run on the child thread if a picture is delivered
+  // the first time so it can be cleared.
+  virtual bool CanDecodeOnIOThread();
+
  protected:
   // Do not delete directly; use Destroy() or own it with a scoped_ptr, which
   // will Destroy() it properly by default.