Introduce GpuVideoDecodeAcceleratorFactory.

content/common/gpu/media/dxva_video_decode_accelerator_win.h

Index: content/common/gpu/media/dxva_video_decode_accelerator_win.h
diff --git a/content/common/gpu/media/dxva_video_decode_accelerator_win.h b/content/common/gpu/media/dxva_video_decode_accelerator_win.h
index 56087b335e8856640b1e69e41bb8fc8ede617aef..f4f474ab17ce8a5905d5ae3ce19ecf77d276ee4a 100644
--- a/content/common/gpu/media/dxva_video_decode_accelerator_win.h
+++ b/content/common/gpu/media/dxva_video_decode_accelerator_win.h
@@ -29,6 +29,7 @@
 #include "base/threading/thread.h"
 #include "base/win/scoped_comptr.h"
 #include "content/common/content_export.h"
+#include "content/common/gpu/media/gpu_video_decode_accelerator_helpers.h"
 #include "media/video/video_decode_accelerator.h"
 
 interface IMFSample;
@@ -97,8 +98,8 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
 
   // Does not take ownership of |client| which must outlive |*this|.
   DXVAVideoDecodeAccelerator(
-      const base::Callback<bool(void)>& make_context_current,
-      gfx::GLContext* gl_context,
+      const GetGLContextCallback& get_gl_context_cb,
+      const MakeGLContextCurrentCallback& make_context_current_cb,
       bool enable_accelerated_vpx_decode);
   ~DXVAVideoDecodeAccelerator() override;
 
@@ -111,7 +112,10 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   void Flush() override;
   void Reset() override;
   void Destroy() override;
-  bool CanDecodeOnIOThread() override;
+  bool TryToSetupDecodeOnSeparateThread(
+      const base::WeakPtr<Client>& decode_client,
+      const scoped_refptr<base::SingleThreadTaskRunner>& decode_task_runner)
+      override;
   GLenum GetSurfaceInternalFormat() const override;
 
   static media::VideoDecodeAccelerator::SupportedProfiles
@@ -391,8 +395,10 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   typedef std::list<base::win::ScopedComPtr<IMFSample>> PendingInputs;
   PendingInputs pending_input_buffers_;
 
+  // Callback to get current GLContext.
+  GetGLContextCallback get_gl_context_cb_;
   // Callback to set the correct gl context.
-  base::Callback<bool(void)> make_context_current_;
+  MakeGLContextCurrentCallback make_context_current_cb_;
 
   // Which codec we are decoding with hardware acceleration.
   media::VideoCodec codec_;
@@ -432,9 +438,6 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   // be initialized. Defaults to true.
   bool dx11_video_format_converter_media_type_needs_init_;
 
-  // The GLContext to be used by the decoder.
-  scoped_refptr<gfx::GLContext> gl_context_;
-
   // Set to true if we are sharing ANGLE's device.
   bool using_angle_device_;