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

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 24f84a5ff2a11a7ff61230439383964cc5d81f9e..86125eda975025da3af7cbca12071e8a1e90570e 100644
--- a/content/common/gpu/media/dxva_video_decode_accelerator.h
+++ b/content/common/gpu/media/dxva_video_decode_accelerator.h
@@ -79,6 +79,9 @@ class CONTENT_EXPORT DXVAVideoDecodeAccelerator
   static media::VideoDecodeAccelerator::SupportedProfiles
       GetSupportedProfiles();
 
+  // Preload dlls required for decoding.
+  static void PreSandboxInitialization();
+
  private:
   typedef void* EGLConfig;
   typedef void* EGLSurface;