Removed webui_generator and new OOBE UI placeholder.

build/gn_migration.gypi

 # Copyright (c) 2015 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.
 
 # This file defines five targets that we are using to track the progress of the
 # GYP->GN migration:
 #
 # 'both_gn_and_gyp' lists what GN is currently capable of building and should
 # match the 'both_gn_and_gyp' target in //BUILD.gn.
 #
@@ skipping 44 matching lines @@
         '../chrome/chrome.gyp:interactive_ui_tests',
         '../chrome/chrome.gyp:load_library_perf_tests',
         '../chrome/chrome.gyp:performance_browser_tests',
         '../chrome/chrome.gyp:sync_integration_tests',
         '../chrome/chrome.gyp:sync_performance_tests',
         '../chrome/chrome.gyp:unit_tests',
         '../chrome/tools/profile_reset/jtl_compiler.gyp:jtl_compiler',
         '../cloud_print/cloud_print.gyp:cloud_print_unittests',
         '../components/components.gyp:network_hints_browser',
         '../components/components.gyp:policy_templates',
-        '../components/components.gyp:webui_generator',
         '../components/components_tests.gyp:components_browsertests',
         '../components/components_tests.gyp:components_perftests',
         '../components/components_tests.gyp:components_unittests',
         '../content/content.gyp:content_app_browser',
         '../content/content.gyp:content_app_child',
         '../content/content_shell_and_tests.gyp:content_browsertests',
         '../content/content_shell_and_tests.gyp:content_gl_benchmark',
         '../content/content_shell_and_tests.gyp:content_gl_tests',
         '../content/content_shell_and_tests.gyp:content_perftests',
         '../content/content_shell_and_tests.gyp:content_shell',
@@ skipping 597 matching lines @@
           'dependencies': [
             # TODO(GYP): All of these targets need to be ported over.
             '../components/components.gyp:policy_win64',
           ]
         }],
       ],
     },
   ]
 }