Remove all the OS X 10.6 SDK forward declarations.

chrome/chrome_browser.gypi

 # 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.
 
 {
   'targets': [
     {
       'target_name': 'browser',
       'type': 'static_library',
@@ skipping 5008 matching lines @@
               '$(SDKROOT)/System/Library/Frameworks/AddressBook.framework',
               '$(SDKROOT)/System/Library/Frameworks/AudioUnit.framework',
               '$(SDKROOT)/System/Library/Frameworks/DiskArbitration.framework',
               '$(SDKROOT)/System/Library/Frameworks/IOKit.framework',
               '$(SDKROOT)/System/Library/Frameworks/OpenGL.framework',
               '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
               '$(SDKROOT)/System/Library/Frameworks/SecurityInterface.framework',
             ],
           },
           'dependencies': [
-            '../base/base.gyp:closure_blocks_leopard_compat',
             '../third_party/icon_family/icon_family.gyp:icon_family',
           ],
           'actions': [
             {
               # This action is used to extract the localization data from xib
               # files and generate table for the ui localizer from it.
               'variables': {
                 'xib_localizer_tool_path':
                     'tools/build/mac/generate_localizer',
                 'xib_files_to_scan': [
@@ skipping 376 matching lines @@
         'browser/metrics/proto/study.proto',
       ],
       'variables': {
         'proto_in_dir': 'browser/metrics/proto',
         'proto_out_dir': 'chrome/browser/metrics/proto',
       },
       'includes': [ '../build/protoc.gypi' ]
     },
   ],
 }