aura: Make GTK a dependency again for chrome/aura etc. to make things buildable.

build/common.gypi

 # Copyright (c) 2011 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.
 
 # IMPORTANT:
 # Please don't directly include this file if you are building via gyp_chromium,
 # since gyp_chromium is automatically forcing its inclusion.
 {
   # Variables expected to be overriden on the GYP command line (-D) or by
   # ~/.gyp/include.gypi.
@@ skipping 231 matching lines @@
           'use_x11%': 0,
         }, {
           # TODO(dnicoara) Wayland build should have these disabled, but
           # currently GTK and X is too spread and it's hard to completely
           # remove every dependency.
           'use_glib%': 1,
           'toolkit_uses_gtk%': 1,
           'use_x11%': 1,
         }],
         ['use_aura==1 and OS!="win"', {
-          'toolkit_uses_gtk%': 0,
+          'toolkit_uses_gtk%': 1,
         }],
 
         # A flag to enable or disable our compile-time dependency
         # on gnome-keyring. If that dependency is disabled, no gnome-keyring
         # support will be available. This option is useful
         # for Linux distributions.
         ['chromeos==1', {
           'use_gnome_keyring%': 0,
         }, {
           'use_gnome_keyring%': 1,
@@ skipping 2143 matching lines @@
     # settings in target dicts.  SYMROOT is a special case, because many other
     # Xcode variables depend on it, including variables such as
     # PROJECT_DERIVED_FILE_DIR.  When a source group corresponding to something
     # like PROJECT_DERIVED_FILE_DIR is added to a project, in order for the
     # files to appear (when present) in the UI as actual files and not red
     # red "missing file" proxies, the correct path to PROJECT_DERIVED_FILE_DIR,
     # and therefore SYMROOT, needs to be set at the project level.
     'SYMROOT': '<(DEPTH)/xcodebuild',
   },
 }