Delete the GTK+ port of Chrome.

chrome/common_constants.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,
   },
 
   'includes': [
@@ skipping 67 matching lines @@
       ],
       'target_conditions': [
         ['OS=="ios"', {
           # iOS needs chrome_paths_mac, which is excluded by filename rules;
           # re-add it in target_conditionals so it's after that exclusion.
           'sources/': [
             ['include', '^common/chrome_paths_mac\\.mm$'],
           ],
         }],
       ],
-      'conditions': [
-        ['toolkit_uses_gtk == 1', {
-          'dependencies': ['../build/linux/system.gyp:gtk'],
-        }],
-      ],
     },
   ],
   'conditions': [
     ['OS=="win" and target_arch=="ia32"', {
       'targets': [
         {
           'target_name': 'common_constants_win64',
           'type': 'static_library',
           'include_dirs': [
             '<(SHARED_INTERMEDIATE_DIR)',  # Needed by chrome_paths.cc.
@@ skipping 11 matching lines @@
           'configurations': {
             'Common_Base': {
               'msvs_target_platform': 'x64',
             },
           },
         },
       ],
     }],
   ],
 }