Remove root_window_ member from DesktopBackgroundController.

ash/shell.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/shell.h"
 
 #include <algorithm>
 #include <string>
 
 #include "ash/accelerators/focus_manager_factory.h"
@@ skipping 540 matching lines @@
   root_window_layout_ = new internal::RootWindowLayoutManager(root_window);
   root_window->SetLayoutManager(root_window_layout_);
 
   event_client_.reset(new internal::EventClientImpl(root_window));
 
   status_area_widget_ = new internal::StatusAreaWidget();
   status_area_widget_->CreateTrayViews(delegate_.get());
   status_area_widget_->Show();
 
   // This controller needs to be set before SetupManagedWindowMode.
-  desktop_background_controller_.reset(
-      new DesktopBackgroundController(root_window));
+  desktop_background_controller_.reset(new DesktopBackgroundController());
   if (delegate_.get())
     user_wallpaper_delegate_.reset(delegate_->CreateUserWallpaperDelegate());
   if (!user_wallpaper_delegate_.get())
     user_wallpaper_delegate_.reset(new DummyUserWallpaperDelegate());
 
   if (delegate_.get())
     user_action_client_.reset(delegate_->CreateUserActionClient());
   if (user_action_client_.get())
     aura::client::SetUserActionClient(root_window, user_action_client_.get());
 
@@ skipping 268 matching lines @@
 void Shell::SetCursor(gfx::NativeCursor cursor) {
   // TODO(oshima): set cursor to all root windows.
   GetPrimaryRootWindow()->SetCursor(cursor);
 }
 
 void Shell::ShowCursor(bool visible) {
   GetPrimaryRootWindow()->ShowCursor(visible);
 }
 
 }  // namespace ash