Update V8 to version 3.12.

tools/gyp/configurations_xcode.gypi

Index: tools/gyp/configurations_xcode.gypi
===================================================================
--- tools/gyp/configurations_xcode.gypi	(revision 11599)
+++ tools/gyp/configurations_xcode.gypi	(working copy)
@@ -1,11 +1,17 @@
-# Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+# Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
+# The purpose of this file and others in this directory is to simulate
+# the Chromium build enviroment. This file is included in all GYP
+# files that are used by the Dart project. This includes V8's GYP
+# files.
+
+# READ BEFORE EDITING:
+# Do not add Dart VM specific configuration to this file. Instead,
+# modify runtime/tools/gyp/runtime-configurations.gypi.
+
 {
-  'variables': {
-    'dart_debug_optimization_level%': '2',
-  },
   'target_defaults': {
     'configurations': {
       'Dart_Base': {
@@ -21,8 +27,6 @@
           'GCC_SYMBOLS_PRIVATE_EXTERN': 'YES', # -fvisibility=hidden
           'GCC_INLINES_ARE_PRIVATE_EXTERN': 'YES', # -fvisibility-inlines-hidden
           'GCC_WARN_NON_VIRTUAL_DESTRUCTOR': 'YES', # -Wnon-virtual-dtor
-          # TODO(v8-team): Fix V8 build.
-          #'GCC_WARN_HIDDEN_VIRTUAL_FUNCTIONS': 'YES', # -Woverloaded-virtual
           'GCC_TREAT_WARNINGS_AS_ERRORS': 'YES', # -Werror
           'WARNING_CFLAGS': [
             '<@(common_gcc_warning_flags)',
@@ -48,37 +52,6 @@
           'PREBINDING': 'NO',
         },
       },
-
-      'Dart_ia32_Base': {
-        'xcode_settings': {
-          'ARCHS': [ 'i386' ],
-        },
-      },
-
-      'Dart_x64_Base': {
-        'xcode_settings': {
-          'ARCHS': [ 'x86_64' ],
-        },
-      },
-
-      'Dart_simarm_Base': {
-        'xcode_settings': {
-          'ARCHS': [ 'i386' ],
-          'GCC_OPTIMIZATION_LEVEL': '3',
-        },
-      },
-
-      'Dart_Debug': {
-        'xcode_settings': {
-          'GCC_OPTIMIZATION_LEVEL': '<(dart_debug_optimization_level)',
-        },
-      },
-
-      'Dart_Release': {
-        'xcode_settings': {
-          'GCC_OPTIMIZATION_LEVEL': '3',
-        },
-      },
     },
   },
 }