Move startup_helper_win.cc to separate target for incremental build

ash/ash.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,
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
     # These files lists are shared with the GN build.
     'ash_sources': [
@@ skipping 697 matching lines @@
       'test/test_system_tray_delegate.cc',
       'test/test_system_tray_delegate.h',
       'test/test_user_wallpaper_delegate.cc',
       'test/test_user_wallpaper_delegate.h',
       'test/test_volume_control_delegate.cc',
       'test/test_volume_control_delegate.h',
       'test/ui_controls_factory_ash.cc',
       'test/ui_controls_factory_ash.h',
     ],
     'ash_shell_lib_sources': [
-      '../content/app/startup_helper_win.cc',
       '../ui/views/test/test_views_delegate_aura.cc',
       'shell/app_list.cc',
       'shell/bubble.cc',
       'shell/content_client/shell_browser_main_parts.cc',
       'shell/content_client/shell_browser_main_parts.h',
       'shell/content_client/shell_content_browser_client.cc',
       'shell/content_client/shell_content_browser_client.h',
       'shell/content_client/shell_main_delegate.cc',
       'shell/content_client/shell_main_delegate.h',
       'shell/context_menu.cc',
@@ skipping 463 matching lines @@
         '../ui/views/views.gyp:views_test_support',
         'ash',
         'ash_resources.gyp:ash_resources',
         'ash_strings.gyp:ash_strings',
         'ash_test_support',
         'ash_with_content',
       ],
       'sources': [
         '<@(ash_shell_lib_sources)',
       ],
+      'conditions': [
+        ['OS=="win"', {
+          'dependencies': [
+            '../content/content.gyp:content_startup_helper_win',
+          ],
+        }],
+      ],
     },
     {
       # GN version: //ash:ash_shell
       'target_name': 'ash_shell',
       'type': 'executable',
       'dependencies': [
         'ash_shell_lib',
         '../components/components.gyp:user_manager',
       ],
       'sources': [
@@ skipping 39 matching lines @@
       'conditions': [
         ['chromeos==1', {
           'dependencies': [
             '../ui/display/display.gyp:display',
           ],
         }],
       ],
     },
   ],
 }