Add VTSupport for dynamically linking VideoToolbox.

content/common/gpu/media/vt.h

+// Copyright 2014 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_VT_H_
+#define CONTENT_COMMON_GPU_MEDIA_VT_H_
+
+// Dynamic library loader.
+#include "content/common/gpu/media/vt_stubs.h"
+
+// CoreMedia and VideoToolbox types.
+#include "content/common/gpu/media/vt_stubs_header.fragment"
+
+// CoreMedia and VideoToolbox functions.
+extern "C" {
+#include "content/common/gpu/media/vt.sig"
+}  // extern "C"
+
+#endif  // CONTENT_COMMON_GPU_MEDIA_VT_H_