Delete the GTK+ port of Chrome.

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': [
     {
       'target_name': 'shell_dialogs',
       'type': '<(component)',
       'dependencies': [
         '../../base/base.gyp:base',
         '../../base/base.gyp:base_i18n',
         '../../skia/skia.gyp:skia',
         '../base/strings/ui_strings.gyp:ui_strings',
         '../base/ui_base.gyp:ui_base',
       ],
       'defines': [
         'SHELL_DIALOGS_IMPLEMENTATION',
       ],
       'sources': [
         'android/shell_dialogs_jni_registrar.cc',
         'android/shell_dialogs_jni_registrar.h',
         'base_shell_dialog.cc',
         'base_shell_dialog.h',
         'base_shell_dialog_win.cc',
         'base_shell_dialog_win.h',
-        'gtk/select_file_dialog_impl.cc',
-        'gtk/select_file_dialog_impl.h',
-        'gtk/select_file_dialog_impl_gtk.cc',
-        'gtk/select_file_dialog_impl_kde.cc',
         'linux_shell_dialog.cc',
         'linux_shell_dialog.h',
         'select_file_dialog.cc',
         'select_file_dialog.h',
         'select_file_dialog_android.cc',
         'select_file_dialog_android.h',
         'select_file_dialog_factory.cc',
         'select_file_dialog_factory.h',
         'select_file_dialog_mac.h',
         'select_file_dialog_mac.mm',
@@ skipping 48 matching lines @@
         '../../base/base.gyp:run_all_unittests',
         '../../testing/gtest.gyp:gtest',
         'shell_dialogs',
       ],
       'sources': [
         'select_file_dialog_win_unittest.cc',
       ],
     },
   ],
 }