make menus, bubbles, etc. top level windows on aura

ui/aura/client/animation_host.cc

Index: ui/aura/client/animation_host.cc
diff --git a/ui/aura/client/animation_host.cc b/ui/aura/client/animation_host.cc
new file mode 100644
index 0000000000000000000000000000000000000000..5df22babc62524d7fcdb5cc4670a380cdb2bc232
--- /dev/null
+++ b/ui/aura/client/animation_host.cc
@@ -0,0 +1,32 @@
+// Copyright 2013 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 "ui/aura/client/animation_host.h"
+
+#include "base/compiler_specific.h"
+#include "ui/aura/aura_export.h"
+
+#include "ui/aura/env.h"
+#include "ui/aura/root_window.h"
+#include "ui/aura/window_property.h"
+
+DECLARE_WINDOW_PROPERTY_TYPE(aura::client::AnimationHost*)
+
+namespace aura {
+namespace client {
+
+DEFINE_WINDOW_PROPERTY_KEY(AnimationHost*, kRootWindowAnimationHostKey, NULL);
+
+void SetAnimationHost(Window* window, AnimationHost* animation_host) {
+  DCHECK(window);
+  window->SetProperty(kRootWindowAnimationHostKey, animation_host);
+}
+
+AnimationHost* GetAnimationHost(Window* window) {
+  DCHECK(window);
+  return window->GetProperty(kRootWindowAnimationHostKey);
+}
+
+}  // namespace client
+}  // namespace aura