Add test to verify that the stacking controller picks the correct activatable window for menu.

ui/aura/test/test_windows.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/test/test_windows.h"
 
 #include "ui/aura/window.h"
 #include "ui/gfx/compositor/layer.h"
 #include "ui/gfx/rect.h"
 
@@ skipping 13 matching lines @@
                          const gfx::Rect& bounds,
                          Window* parent) {
   return CreateTestWindowWithDelegate(new ColorTestWindowDelegate(color),
                                       id, bounds, parent);
 }
 
 Window* CreateTestWindowWithDelegate(WindowDelegate* delegate,
                                      int id,
                                      const gfx::Rect& bounds,
                                      Window* parent) {
+  return CreateTestWindowWithDelegateAndType(
+      delegate,
+      aura::WINDOW_TYPE_NORMAL,
+      id,
+      bounds,
+      parent);
+}
+
+Window* CreateTestWindowWithDelegateAndType(WindowDelegate* delegate,
+                                            WindowType type,
+                                            int id,
+                                            const gfx::Rect& bounds,
+                                            Window* parent) {
   Window* window = new Window(delegate);
   window->set_id(id);
-  window->SetType(aura::WINDOW_TYPE_NORMAL);
+  window->SetType(type);
   window->Init(ui::Layer::LAYER_HAS_TEXTURE);
   window->SetBounds(bounds);
   window->Show();
   window->SetParent(parent);
   return window;
 }
 
 }  // namespace test
 }  // namespace aura