Enable find-missing-symbols-at-link-time for chromeos builds too.

components/wallpaper.gypi

 # Copyright 2014 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.
 {
   'targets': [
     {
       'target_name': 'wallpaper',
       'type': '<(component)',
       'dependencies': [
         '../base/base.gyp:base',
+        '../base/base.gyp:base_prefs',
+        '../content/content.gyp:content',
         '../skia/skia.gyp:skia',
         '../ui/gfx/gfx.gyp:gfx',
         '../ui/gfx/gfx.gyp:gfx_geometry',
+        '../url/url.gyp:url_lib',
       ],
       'include_dirs': [
         '..',
       ],
       'defines':[
         'WALLPAPER_IMPLEMENTATION',
       ],
       'sources': [
         'wallpaper/wallpaper_layout.h',
         'wallpaper/wallpaper_resizer.cc',
         'wallpaper/wallpaper_resizer.h',
         'wallpaper/wallpaper_resizer_observer.h',
       ],
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '../chromeos/chromeos.gyp:chromeos',
             '../components/components.gyp:user_manager',
           ],
           'sources': [
             'wallpaper/wallpaper_manager_base.cc',
             'wallpaper/wallpaper_manager_base.h',
           ],
         }],
       ],
     },
   ],
 }