Reland "Fix white flash when user signs out and fix wallpaper animation regression"

ash/desktop_background/desktop_background_widget_controller.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_widget_controller.h"
 
 #include "ui/aura/root_window.h"
 #include "ui/views/widget/widget.h"
 
 DECLARE_WINDOW_PROPERTY_TYPE(ash::internal::DesktopBackgroundWidgetController*);
+DECLARE_WINDOW_PROPERTY_TYPE(ash::internal::ComponentWrapper*);
 
 namespace ash {
 namespace internal {
 
 DEFINE_OWNED_WINDOW_PROPERTY_KEY(DesktopBackgroundWidgetController,
                                  kWindowDesktopComponent, NULL);
+DEFINE_OWNED_WINDOW_PROPERTY_KEY(ComponentWrapper, kComponentWrapper, NULL);
 
 DesktopBackgroundWidgetController::DesktopBackgroundWidgetController(
     views::Widget* widget) : widget_(widget) {
 }
 
 DesktopBackgroundWidgetController::DesktopBackgroundWidgetController(
     ui::Layer* layer) : widget_(NULL) {
   layer_.reset(layer);
 }
 
 DesktopBackgroundWidgetController::~DesktopBackgroundWidgetController() {
   if (widget_) {
     widget_->CloseNow();
     widget_ = NULL;
   } else if (layer_.get())
     layer_.reset(NULL);
 }
 
 void DesktopBackgroundWidgetController::SetBounds(gfx::Rect bounds) {
   if (widget_)
     widget_->SetBounds(bounds);
   else if (layer_.get())
     layer_->SetBounds(bounds);
 }
 
-
 void DesktopBackgroundWidgetController::Reparent(aura::RootWindow* root_window,
                                                  int src_container,
                                                  int dest_container) {
   if (widget_) {
     views::Widget::ReparentNativeView(widget_->GetNativeView(),
         root_window->GetChildById(dest_container));
   } else if (layer_.get()) {
     ui::Layer* layer = layer_.get();
     root_window->GetChildById(src_container)->layer()->Remove(layer);
     root_window->GetChildById(dest_container)->layer()->Add(layer);
   }
 }
 
+ComponentWrapper::ComponentWrapper(
+    DesktopBackgroundWidgetController* component) : component_(component) {
+}
+
 }  // namespace internal
 }  // namespace ash