Move startup_helper_win.cc to separate target for incremental build

ui/app_list/app_list.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': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 266 matching lines @@
       'msvs_disabled_warnings': [ 4267, ],
     },
   ],
   'conditions': [
     ['toolkit_views==1', {
       'targets': [
         {
           'target_name': 'app_list_demo',
           'type': 'executable',
           'sources': [
-            '../../content/app/startup_helper_win.cc',
             'demo/app_list_demo_views.cc',
           ],
           'dependencies': [
             '../../base/base.gyp:base',
             '../../content/content.gyp:content',
             '../../content/content.gyp:content_browser',
             '../../skia/skia.gyp:skia',
             '../../url/url.gyp:url_lib',
             '../base/ui_base.gyp:ui_base',
             '../events/events.gyp:events',
             '../resources/ui_resources.gyp:ui_resources',
             '../resources/ui_resources.gyp:ui_test_pak',
             '../views/controls/webview/webview.gyp:webview',
             '../views/views.gyp:views',
             '../views_content_client/views_content_client.gyp:views_content_client',
             'app_list',
             'app_list_test_support',
           ],
           'conditions': [
             ['OS=="win"', {
               'msvs_settings': {
                 'VCLinkerTool': {
                   'SubSystem': '2',  # Set /SUBSYSTEM:WINDOWS
                 },
               },
               'dependencies': [
                 '../../sandbox/sandbox.gyp:sandbox',
+                '../../content/content.gyp:content_startup_helper_win',
               ],
             }],
           ],
         },
       ],
     }],  # toolkit_views==1
   ],
 }