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

ui/views/widget/desktop_aura/desktop_native_widget_aura.h

 // 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.
 
 #ifndef UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_
 #define UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_
 
 #include <string>
 
 #include "base/macros.h"
@@ skipping 240 matching lines @@
   DesktopWindowTreeHost* desktop_window_tree_host_;
 
   // See class documentation for Widget in widget.h for a note about ownership.
   Widget::InitParams::Ownership ownership_;
 
   // Internal name.
   std::string name_;
 
   std::unique_ptr<DesktopCaptureClient> capture_client_;
 
-  // Child of the root, contains |content_window_|.
-  aura::Window* content_window_container_;
-
-  // Child of |content_window_container_|. This is the return value from
-  // GetNativeView().
+  // This is the return value from GetNativeView().
   // WARNING: this may be NULL, in particular during shutdown it becomes NULL.
   aura::Window* content_window_;
 
   internal::NativeWidgetDelegate* native_widget_delegate_;
 
   std::unique_ptr<wm::FocusController> focus_client_;
   std::unique_ptr<aura::client::ScreenPositionClient> position_client_;
   std::unique_ptr<aura::client::DragDropClient> drag_drop_client_;
   std::unique_ptr<aura::client::WindowParentingClient> window_parenting_client_;
   std::unique_ptr<DesktopEventClient> event_client_;
@@ skipping 40 matching lines @@
   // The following factory is used for calls to close the NativeWidgetAura
   // instance.
   base::WeakPtrFactory<DesktopNativeWidgetAura> close_widget_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DesktopNativeWidgetAura);
 };
 
 }  // namespace views
 
 #endif  // UI_VIEWS_WIDGET_DESKTOP_AURA_DESKTOP_NATIVE_WIDGET_AURA_H_