mac: Switch from -O3 to -O2.

build/common.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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 2475 matching lines @@
           # See http://msdn.microsoft.com/en-us/library/aa652367.aspx
           'win_release_RuntimeLibrary%': '0', # 0 = /MT (nondebug static)
           'win_debug_RuntimeLibrary%': '1',   # 1 = /MTd (debug static)
         }],
         ['OS=="ios"', {
           # See http://gcc.gnu.org/onlinedocs/gcc-4.4.2/gcc/Optimize-Options.html
           'mac_release_optimization%': 's', # Use -Os unless overridden
           'mac_debug_optimization%': '0',   # Use -O0 unless overridden
         }, {
           # See http://gcc.gnu.org/onlinedocs/gcc-4.4.2/gcc/Optimize-Options.html
-          'mac_release_optimization%': '3', # Use -O3 unless overridden
+          'mac_release_optimization%': '2', # Use -O2 unless overridden
           'mac_debug_optimization%': '0',   # Use -O0 unless overridden
         }],
         ['OS=="android"', {
           'host_os%': '<(host_os)',  # See comment above chromium_code.
         }],
       ],
       'clang_warning_flags': [
         '-Wheader-hygiene',
 
         # Don't die on dtoa code that uses a char as an array index.
@@ skipping 3416 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }