Eliminate Shell::RootWindowList in favor of aura::Window::Windows.

ash/desktop_background/desktop_background_view.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 "ash/desktop_background/desktop_background_view.h"
 
 #include <limits>
 
 #include "ash/ash_export.h"
 #include "ash/desktop_background/desktop_background_controller.h"
@@ skipping 156 matching lines @@
   return true;
 }
 
 void DesktopBackgroundView::ShowContextMenuForView(
     views::View* source,
     const gfx::Point& point,
     ui::MenuSourceType source_type) {
   Shell::GetInstance()->ShowContextMenu(point, source_type);
 }
 
-views::Widget* CreateDesktopBackground(aura::RootWindow* root_window,
+views::Widget* CreateDesktopBackground(aura::Window* root_window,
                                        int container_id) {
   DesktopBackgroundController* controller =
       Shell::GetInstance()->desktop_background_controller();
   UserWallpaperDelegate* wallpaper_delegate =
       Shell::GetInstance()->user_wallpaper_delegate();
 
   views::Widget* desktop_widget = new views::Widget;
   views::Widget::InitParams params(
       views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
   if (controller->GetWallpaper().isNull())
@@ skipping 24 matching lines @@
     views::corewm::SetWindowVisibilityAnimationTransition(
         desktop_widget->GetNativeView(), views::corewm::ANIMATE_NONE);
   }
 
   desktop_widget->SetBounds(params.parent->bounds());
   return desktop_widget;
 }
 
 }  // namespace internal
 }  // namespace ash