Remove remote tree host and some related input and metro_driver code

ui/shell_dialogs/shell_dialogs.gyp

 # Copyright 2013 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 56 matching lines @@
             'include_dirs': [
               '<(SHARED_INTERMEDIATE_DIR)/ui',
             ],
             'link_settings': {
               'libraries': [
                 '-ljnigraphics',
               ],
             },
           }
         ],
-        ['OS=="win"',
-          {
-            'dependencies': [
-              '../../win8/win8.gyp:metro_viewer',
-            ],
-          }
-        ],
       ],
     },  # target_name: shell_dialogs
     {
       # GN version: //ui/shell_dialogs:shell_dialogs_unittests
       'target_name': 'shell_dialogs_unittests',
       'type': 'executable',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../base/base.gyp:test_support_base',
         '../../base/base.gyp:run_all_unittests',
         '../../testing/gtest.gyp:gtest',
         'shell_dialogs',
       ],
       'sources': [
         # Note: file list duplicated in GN build.
         'select_file_dialog_win_unittest.cc',
       ],
     },
   ],
 }