aura: Make 'ui' buildable without gtk.

ui/aura/demo/demo_main.cc

 // 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.
 
 #include "base/at_exit.h"
 #include "base/command_line.h"
 #include "base/i18n/icu_util.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/message_loop.h"
 #include "third_party/skia/include/core/SkXfermode.h"
@@ skipping 54 matching lines @@
 int main(int argc, char** argv) {
   CommandLine::Init(argc, argv);
 
   // The exit manager is in charge of calling the dtors of singleton objects.
   base::AtExitManager exit_manager;
 
   ui::RegisterPathProvider();
   icu_util::Initialize();
   ResourceBundle::InitSharedInstance("en-US");
 
-#if defined(USE_X11)
+#if defined(TOOLKIT_USES_GTK)
   base::MessagePumpX::DisableGtkMessagePump();
 #endif
 
   // Create the message-loop here before creating the desktop.
   MessageLoop message_loop(MessageLoop::TYPE_UI);
 
   aura::Desktop::GetInstance();
 
   // Create a hierarchy of test windows.
   DemoWindowDelegate window_delegate1(SK_ColorBLUE);
@@ skipping 17 matching lines @@
   window3.set_id(3);
   window3.Init();
   window3.SetBounds(gfx::Rect(10, 10, 50, 50), 0);
   window3.SetVisibility(aura::Window::VISIBILITY_SHOWN);
   window3.SetParent(&window2);
 
   aura::Desktop::GetInstance()->Run();
   return 0;
 }