desktop-views: Create one fewer aura::Window for each widget.

ui/views/widget/desktop_aura/desktop_focus_rules.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/views/widget/desktop_aura/desktop_focus_rules.h"
 
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 
 namespace views {
 
 DesktopFocusRules::DesktopFocusRules(aura::Window* content_window)
     : content_window_(content_window) {}
 
 DesktopFocusRules::~DesktopFocusRules() {}
 
 bool DesktopFocusRules::CanActivateWindow(aura::Window* window) const {
   if (!BaseFocusRules::CanActivateWindow(window))
     return false;
   // Never activate a window that is not a child of the root window. Transients
   // spanning different DesktopNativeWidgetAuras may trigger this.
   return !window || content_window_->GetRootWindow()->Contains(window);
 }
 
 bool DesktopFocusRules::SupportsChildActivation(aura::Window* window) const {
   // In Desktop-Aura, only the content_window or children of the RootWindow are
   // activatable.
-  return window == content_window_->parent() ||
-         window->GetRootWindow() == window;
+  return window->IsRootWindow();
 }
 
 bool DesktopFocusRules::IsWindowConsideredVisibleForActivation(
     aura::Window* window) const {
   // |content_window_| is initially hidden and made visible from Show(). Even in
   // this state we still want it to be active.
   return BaseFocusRules::IsWindowConsideredVisibleForActivation(window) ||
       (window == content_window_);
 }
 
@@ skipping 15 matching lines @@
   // In Desktop-Aura the content_window_'s parent is a dummy window and thus
   // should never be activated. We should return the content_window_ if it
   // can be activated in this case.
   if (next_activatable_window == content_window_->parent() &&
       CanActivateWindow(content_window_))
     return content_window_;
   return next_activatable_window;
 }
 
 }  // namespace views