Better Z-index support.

ui/aura/toplevel_window_container.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 "ui/aura/toplevel_window_container.h"
+
+#include "ui/aura/toplevel_window_event_filter.h"
+
+namespace aura {
+namespace internal {
+
+ToplevelWindowContainer::ToplevelWindowContainer()
+    : Window(NULL) {
+  set_name(L"ToplevelWindowContainer");
+  SetEventFilter(new ToplevelWindowEventFilter(this));
+}
+
+ToplevelWindowContainer::~ToplevelWindowContainer() {
+}
+
+bool ToplevelWindowContainer::IsToplevelWindowContainer() const {
+  return true;
+}
+
+}  // namespace internal
+}  // namespace aura