Preload the media foundation, h.264 decoder and the dxva2.dll before the gpu sandbox is initialized.

content/common/gpu/media/dxva_video_decode_accelerator.h

 // Copyright (c) 2012 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_DXVA_VIDEO_DECODE_ACCELERATOR_H_
 #define CONTENT_COMMON_GPU_MEDIA_DXVA_VIDEO_DECODE_ACCELERATOR_H_
 
 #include <d3d11.h>
 #include <d3d9.h>
 // Work around bug in this header by disabling the relevant warning for it.
@@ skipping 61 matching lines @@
   void ReusePictureBuffer(int32 picture_buffer_id) override;
   void Flush() override;
   void Reset() override;
   void Destroy() override;
   bool CanDecodeOnIOThread() override;
   GLenum GetSurfaceInternalFormat() const override;
 
   static media::VideoDecodeAccelerator::SupportedProfiles
       GetSupportedProfiles();
 
+  // Preload dlls required for decoding.
+  static void PreSandboxInitialization();
+
  private:
   typedef void* EGLConfig;
   typedef void* EGLSurface;
 
   // 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.
   bool CreateD3DDevManager();
 
   // Creates and initializes an instance of the DX11 device and the
@@ skipping 281 matching lines @@
 
   // Function pointer for the MFCreateDXGIDeviceManager API.
   static CreateDXGIDeviceManager create_dxgi_device_manager_;
 
   DISALLOW_COPY_AND_ASSIGN(DXVAVideoDecodeAccelerator);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_COMMON_GPU_MEDIA_DXVA_VIDEO_DECODE_ACCELERATOR_H_