reland of https://codereview.chromium.org/11364053/ w/o removing the per-rootwindow stacking client

ui/aura/window.cc

 // 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.
 
 #include "ui/aura/window.h"
 
 #include <algorithm>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
@@ skipping 22 matching lines @@
 #include "ui/gfx/screen.h"
 
 namespace aura {
 
 namespace {
 
 Window* GetParentForWindow(Window* window, Window* suggested_parent) {
   if (suggested_parent)
     return suggested_parent;
   if (client::GetStackingClient())
-    return client::GetStackingClient()->GetDefaultParent(window, gfx::Rect());
+    return client::GetStackingClient()->GetDefaultParent(
+        window, window, gfx::Rect());
   return NULL;
 }
 
 }  // namespace
 
 Window::TestApi::TestApi(Window* window) : window_(window) {}
 
 bool Window::TestApi::OwnsLayer() const {
   return !!window_->layer_owner_.get();
 }
@@ skipping 914 matching lines @@
   bool contains_mouse = false;
   if (IsVisible()) {
     RootWindow* root_window = GetRootWindow();
     contains_mouse = root_window &&
         ContainsPointInRoot(root_window->GetLastMouseLocationInRoot());
   }
   return contains_mouse;
 }
 
 }  // namespace aura