Add support for GYP_DEFINES aura_wm=1 which also defines views_compositor=1.

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 "aura/desktop.h"
 #include "aura/desktop_host.h"
 #include "aura/window.h"
 #include "aura/window_delegate.h"
 #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"
 #include "ui/base/resource/resource_bundle.h"
+#include "ui/base/ui_base_paths.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/canvas_skia.h"
 #include "ui/gfx/rect.h"
-#include "ui/base/ui_base_paths.h"
 
 namespace {
 
 // Trivial WindowDelegate implementation that draws a blue background.
 class DemoWindowDelegate : public aura::WindowDelegate {
  public:
   explicit DemoWindowDelegate(aura::Window* window, SkColor color);
 
   virtual void OnPaint(const gfx::Rect& bounds) OVERRIDE;
 
@@ skipping 66 matching lines @@
   window3.set_delegate(&window_delegate3);
 
   window2.AddChild(&window3);
 
   host->Show();
 
   MessageLoop main_message_loop(MessageLoop::TYPE_UI);
   MessageLoopForUI::current()->Run(host.get());
   return 0;
 }