Adds code for a new Aura shell.

build/common.gypi

 # Copyright (c) 2011 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 643 matching lines @@
       }],
       ['chromeos==1', {
         'grit_defines': ['-D', 'chromeos'],
       }],
       ['toolkit_views==1', {
         'grit_defines': ['-D', 'toolkit_views'],
       }],
       ['use_only_pure_views==1', {
         'grit_defines': ['-D', 'use_only_pure_views'],
       }],
+      ['use_aura==1', {
+        'grit_defines': ['-D', 'use_aura'],
+      }],
       ['touchui==1', {
         'grit_defines': ['-D', 'touchui'],
       }],
       ['webui_dialogs==1', {
         'grit_defines': ['-D', 'webui_dialogs'],
       }],
       ['file_manager_extension==1', {
         'grit_defines': ['-D', 'file_manager_extension'],
       }],
       ['webui_task_manager==1', {
@@ skipping 1374 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',
   },
 }