linux_aura: Use GTK button borders in GTK theme mode.

chrome/browser/ui/libgtk2ui/libgtk2ui.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,
   },
   'targets': [
     {
@@ skipping 27 matching lines @@
       # in a non-gtk build.
       'sources': [
         'app_indicator_icon.cc',
         'app_indicator_icon.h',
         'chrome_gtk_frame.cc',
         'chrome_gtk_frame.h',
         'chrome_gtk_menu_subclasses.cc',
         'chrome_gtk_menu_subclasses.h',
         'gconf_titlebar_listener.cc',
         'gconf_titlebar_listener.h',
+        'gtk2_border.cc',
+        'gtk2_border.h',
         'gtk2_ui.cc',
         'gtk2_ui.h',
         'gtk2_util.cc',
         'gtk2_util.h',
         'libgtk2ui_export.h',
         'menu_util.cc',
         'menu_util.h',
         'native_theme_gtk2.cc',
         'native_theme_gtk2.h',
         'owned_widget_gtk2.cc',
@@ skipping 17 matching lines @@
         ['use_gconf==0', {
           'sources!': [
             'gconf_titlebar_listener.cc',
             'gconf_titlebar_listener.h',
           ],
         }],
       ],
     },
   ],
 }