Removed webui_generator and new OOBE UI placeholder.

components/webui_generator.gypi

-# Copyright 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.
-
-{
-  'targets': [{
-    # GN version: //components/webui_generator
-    'target_name': 'webui_generator',
-    'type': '<(component)',
-    'dependencies': [
-      'login',
-      '<(DEPTH)/base/base.gyp:base',
-      '<(DEPTH)/components/components_resources.gyp:components_resources',
-      '<(DEPTH)/content/content.gyp:content_browser',
-      '<(DEPTH)/ui/base/ui_base.gyp:ui_base',
-    ],
-    'export_dependent_settings': [
-      'login',
-      '<(DEPTH)/base/base.gyp:base',
-      '<(DEPTH)/content/content.gyp:content_browser',
-    ],
-    'defines': [
-      'WUG_IMPLEMENTATION',
-    ],
-    'sources': [
-      'webui_generator/data_source_util.cc',
-      'webui_generator/data_source_util.h',
-      'webui_generator/export.h',
-      'webui_generator/view.cc',
-      'webui_generator/view.h',
-      'webui_generator/view_model.cc',
-      'webui_generator/view_model.h',
-      'webui_generator/web_ui_view.cc',
-      'webui_generator/web_ui_view.h',
-    ],
-  }],
-}