Enable toolkit_views=1 by default on Mac

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 179 matching lines @@
         #   2: revision 2
         'mips_dsp_rev%': 0,
 
         'conditions': [
           # Ash needs Aura.
           ['use_aura==0', {
             'use_ash%': 0,
           }],
 
           # Set default value of toolkit_views based on OS.
-          ['OS=="win" or chromeos==1 or use_aura==1', {
+          ['OS=="mac" or OS=="win" or chromeos==1 or use_aura==1', {
             'toolkit_views%': 1,
           }, {
             'toolkit_views%': 0,
           }],
 
           # Embedded builds use aura without ash or views.
           ['embedded==1', {
             'use_aura%': 1,
             'use_ash%': 0,
             'toolkit_views%': 0,
@@ skipping 5816 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',
   },
 }