Remove all the OS X 10.6 SDK forward declarations.

ui/gfx/video_decode_acceleration_support_mac.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 UI_GFX_VIDEO_DECODE_ACCELERATION_SUPPORT_MAC_H_
 #define UI_GFX_VIDEO_DECODE_ACCELERATION_SUPPORT_MAC_H_
 
 #include <CoreFoundation/CoreFoundation.h>
 #include <CoreVideo/CoreVideo.h>
 #include <map>
 
-#if defined(MAC_OS_X_VERSION_10_6) && \
-    MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_6
 #include <VideoDecodeAcceleration/VDADecoder.h>
-#endif
 
 #include "base/basictypes.h"
 #include "base/callback.h"
 #include "base/gtest_prod_util.h"
 #include "base/memory/ref_counted.h"
 #include "base/message_loop_proxy.h"
 #include "ui/base/ui_export.h"
 
 class FrameCallbackUtil;
 class VideoDecodeAccelerationSupportTest;
 
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-typedef struct OpaqueVDADecoder*  VDADecoder;
-#endif
-
 namespace gfx {
 
 // This Mac OS X-specific class provides dynamically linked access to
 // VideoDecodeAcceleration.framework, which is only available on 10.6 and later.
 class UI_EXPORT VideoDecodeAccelerationSupport :
     public base::RefCountedThreadSafe<VideoDecodeAccelerationSupport> {
  public:
   enum Status {
     SUCCESS = 0,
     LOAD_FRAMEWORK_ERROR,
@@ skipping 49 matching lines @@
   // A reference to the message loop that this object was created on. This is
   // used to invoke the frame ready callback on the correct thread.
   scoped_refptr<base::MessageLoopProxy> loop_;
 
   DISALLOW_COPY_AND_ASSIGN(VideoDecodeAccelerationSupport);
 };
 
 }  // namespace gfx
 
 #endif  // UI_GFX_VIDEO_DECODE_ACCELERATION_SUPPORT_MAC_H_