Remove all the OS X 10.6 SDK forward declarations.

media/audio/mac/audio_input_mac.cc

 // 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.
 
 #include "media/audio/mac/audio_input_mac.h"
 
 #include <CoreServices/CoreServices.h>
 
 #include "base/basictypes.h"
 #include "base/logging.h"
 #include "media/audio/audio_util.h"
 #include "media/audio/mac/audio_manager_mac.h"
 
-#if !defined(MAC_OS_X_VERSION_10_6) || \
-    MAC_OS_X_VERSION_MAX_ALLOWED < MAC_OS_X_VERSION_10_6
-enum {
-  kAudioQueueErr_EnqueueDuringReset = -66632
-};
-#endif
-
 namespace media {
 
 PCMQueueInAudioInputStream::PCMQueueInAudioInputStream(
     AudioManagerMac* manager, const AudioParameters& params)
     : manager_(manager),
       callback_(NULL),
       audio_queue_(NULL),
       buffer_size_bytes_(0),
       started_(false) {
   // We must have a manager.
@@ skipping 183 matching lines @@
       // complications than it solves (memory barrier issues accessing it from
       // multiple threads, looses the means to indicate OnClosed to client).
       // Should determine if we need to do something equivalent here.
       return;
     }
     HandleError(err);
   }
 }
 
 }  // namespace media