Add VTSupport for dynamically linking VideoToolbox.

content/common/gpu/media/vt_stubs_header.fragment

+// 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.
+
+// Declare CoreMedia types. For SDKs >= 10.7, use CoreMedia headers.
+#if !defined(MAC_OS_X_VERSION_10_7) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_7
+
+#include <CoreFoundation/CoreFoundation.h>
+
+extern "C" {
+
+typedef signed long CMItemCount;
+typedef uint32_t CMBlockBufferFlags;
+typedef struct OpaqueCMBlockBuffer *CMBlockBufferRef;
+typedef const struct opaqueCMFormatDescription *CMFormatDescriptionRef;
+typedef CMFormatDescriptionRef CMVideoFormatDescriptionRef;
+typedef struct opaqueCMSampleBuffer *CMSampleBufferRef;
+
+typedef int64_t CMTimeValue;
+typedef int32_t CMTimeScale;
+typedef int64_t CMTimeEpoch;
+typedef uint32_t CMTimeFlags;
+
+typedef struct {
+  CMTimeValue value;
+  CMTimeScale timescale;
+  CMTimeFlags flags;
+  CMTimeEpoch epoch;
+} CMTime;
+
+typedef struct {
+  CMTime duration;
+  CMTime presentationTimeStamp;
+  CMTime decodeTimeStamp;
+} CMSampleTimingInfo;
+
+typedef struct {
+  int32_t width;
+  int32_t height;
+} CMVideoDimensions;
+
+typedef struct {
+  uint32_t version;
+  void *(*AllocateBlock)(void *refCon, size_t sizeInBytes);
+  void (*FreeBlock)(void *refCon, void *doomedMemoryBlock, size_t sizeInBytes);
+  void *refCon;
+} CMBlockBufferCustomBlockSource;
+
+typedef OSStatus (*CMSampleBufferMakeDataReadyCallback)(
+    CMSampleBufferRef sbuf,
+    void *makeDataReadyRefcon);
+
+}  // extern "C"
+
+#else
+#include <CoreMedia/CoreMedia.h>
+#endif
+
+// Declare VideoToolbox types. For SDKs >= 10.8, use VideoToolbox headers.
+#if !defined(MAC_OS_X_VERSION_10_8) || \
+    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_8
+
+extern "C" {
+
+typedef struct __CVBuffer *CVBufferRef;
+typedef CVBufferRef CVImageBufferRef;
+typedef uint32_t VTDecodeFrameFlags;
+typedef UInt32 VTDecodeInfoFlags;
+typedef struct OpaqueVTDecompressionSession* VTDecompressionSessionRef;
+
+typedef void (*VTDecompressionOutputCallback)(
+    void *decompressionOutputRefCon,
+    void *sourceFrameRefCon,
+    OSStatus status,
+    VTDecodeInfoFlags infoFlags,
+    CVImageBufferRef imageBuffer,
+    CMTime presentationTimeStamp,
+    CMTime presentationDuration);
+
+typedef struct {
+  VTDecompressionOutputCallback decompressionOutputCallback;
+  void *decompressionOutputRefCon;
+} VTDecompressionOutputCallbackRecord;
+
+}  // extern "C"
+
+#else
+#include <VideoToolbox/VideoToolbox.h>
+#endif