Enable Aura for all ChromeOS builds in Chromium.

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 45 matching lines @@
           [ 'OS=="win" or OS=="mac"', {
             'host_arch%': 'ia32',
           }, {
             # This handles the Unix platforms for which there is some support.
             # Anything else gets passed through, which probably won't work very
             # well; such hosts should pass an explicit target_arch to gyp.
             'host_arch%':
               '<!(uname -m | sed -e "s/i.86/ia32/;s/x86_64/x64/;s/amd64/x64/;s/arm.*/arm/;s/i86pc/ia32/")',
           }],
 
-          # Ash requires Aura.
-          ['use_ash==1', {
+          # Ash and ChromeOS require Aura.
+          ['use_ash==1 or chromeos==1', {
             'use_aura%': 1,
           }],
 
           # Set default value of toolkit_views based on OS.
           ['OS=="win" or chromeos==1 or use_aura==1', {
             'toolkit_views%': 1,
           }, {
             'toolkit_views%': 0,
           }],
         ],
@@ skipping 2660 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',
   },
 }