Remove all uses of toolkit_use_gtk in the gyp files.

webkit/common/webkit_common.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': {
     'enable_wexit_time_destructors': 1,
     'chromium_code': 1
   },
   'targets': [
@@ skipping 35 matching lines @@
         'resource_response_info.cc',
         'resource_response_info.h',
         'resource_type.cc',
         'resource_type.h',
         'webkit_common_export.h',
         'webpreferences.cc',
         'webpreferences.h',
       ],
 
       'conditions': [
-        ['toolkit_uses_gtk == 1', {
-          'dependencies': [
-            '<(DEPTH)/build/linux/system.gyp:gtk',
-          ],
-          'sources/': [['exclude', '_x11\\.cc$']],
-        }],
         ['use_aura==1 and use_x11==1', {
           'dependencies': [
             '<(DEPTH)/build/linux/system.gyp:xcursor',
           ],
         }],
         ['OS=="mac"', {
           'link_settings': {
             'libraries': [
               '$(SDKROOT)/System/Library/Frameworks/QuartzCore.framework',
             ],
           },
         }],
         ['OS=="win"', {
           # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
           'msvs_disabled_warnings': [ 4800, 4267 ],
         }],
       ],
     },
   ],
 }