Only include ash_strings if use_ash==1.

chrome/chrome_resources.gyp

 # 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.
 {
   'variables': {
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
     'about_credits_file': '<(SHARED_INTERMEDIATE_DIR)/about_credits.html',
     'additional_modules_list_file': '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/internal/additional_modules_list.txt',
     'repack_locales_cmd': ['python', 'tools/build/repack_locales.py'],
   },
@@ skipping 364 matching lines @@
         {
           'includes': ['chrome_repack_chrome_200_percent.gypi']
         },
         {
           'includes': ['chrome_repack_chrome_touch_100_percent.gypi']
         },
       ],
       'conditions': [
         ['OS != "ios"', {
           'dependencies': [
-            # TODO(zork): Protect this with if use_aura==1
-            '<(DEPTH)/ash/ash_strings.gyp:ash_strings',
             '<(DEPTH)/content/content_resources.gyp:content_resources',
             '<(DEPTH)/device/bluetooth/bluetooth_strings.gyp:device_bluetooth_strings',
             '<(DEPTH)/webkit/webkit_resources.gyp:webkit_resources',
             '<(DEPTH)/webkit/webkit_resources.gyp:webkit_strings',
           ],
         }],
         ['use_ash==1', {
           'dependencies': [
+             '<(DEPTH)/ash/ash_strings.gyp:ash_strings',
              '<(DEPTH)/ash/ash.gyp:ash_resources',
           ],
         }],
         ['OS != "mac" and OS != "ios"', {
           # Copy pak files to the product directory. These files will be picked
           # up by the following installer scripts:
           #   - Windows: chrome/installer/mini_installer/chrome.release
           #   - Linux: chrome/installer/linux/internal/common/installer.include
           # Ensure that the above scripts are updated when adding or removing
           # pak files.
@@ skipping 96 matching lines @@
                      '<(generator_path)',
                      'credits',
                      '<(about_credits_file)',
           ],
           'message': 'Generating about:credits',
         },
       ],
     },
   ], # targets
 }