aura: Have aura and aura_demo build and run without gtk on linux.

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 219 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%': 1,
+          'toolkit_uses_gtk%': 0,
         }],
 
         # 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 839 matching lines @@
           ['OS!="win"', {
             'sources/': [ ['exclude', '_win(_unittest)?\\.(h|cc)$'],
                           ['exclude', '(^|/)win/'],
                           ['exclude', '(^|/)win_[^/]*\\.(h|cc)$'] ],
           }],
           ['OS!="mac"', {
             'sources/': [ ['exclude', '_(cocoa|mac)(_unittest)?\\.(h|cc)$'],
                           ['exclude', '(^|/)(cocoa|mac)/'],
                           ['exclude', '\\.mm?$' ] ],
           }],
+          ['use_x11!=1', {
+            'sources/': [
+              ['exclude', '_(chromeos|x|x11)(_unittest)?\\.(h|cc)$'],
+              ['exclude', '(^|/)x11_[^/]*\\.(h|cc)$'],
+            ],
+          }],
           ['toolkit_uses_gtk!=1', {
             'sources/': [
-              ['exclude', '_(chromeos|gtk|x|x11|xdg)(_unittest)?\\.(h|cc)$'],
+              ['exclude', '_(gtk|xdg)(_unittest)?\\.(h|cc)$'],
               ['exclude', '(^|/)gtk/'],
-              ['exclude', '(^|/)(gtk|x11)_[^/]*\\.(h|cc)$'],
+              ['exclude', '(^|/)gtk_[^/]*\\.(h|cc)$'],
             ],
           }],
           ['use_wayland!=1', {
             'sources/': [
               ['exclude', '_(wayland)(_unittest)?\\.(h|cc)$'],
               ['exclude', '(^|/)wayland/'],
               ['exclude', '(^|/)(wayland)_[^/]*\\.(h|cc)$'],
             ],
           }],
           ['OS!="linux"', {
@@ skipping 1275 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',
   },
 }