Invalidate all wallpaper cache if display configuration changed

ash/default_user_wallpaper_delegate.cc

 // Copyright 2013 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/default_user_wallpaper_delegate.h"
 
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/shell.h"
 
 namespace ash {
 
 int DefaultUserWallpaperDelegate::GetAnimationType() {
   return views::corewm::WINDOW_VISIBILITY_ANIMATION_TYPE_FADE;
 }
 
 int DefaultUserWallpaperDelegate::GetAnimationDurationOverride() {
   return 0;
 }
 
 void DefaultUserWallpaperDelegate::SetAnimationDurationOverride(
     int animation_duration_in_ms) {
 }
 
 bool DefaultUserWallpaperDelegate::ShouldShowInitialAnimation() {
   return false;
 }
 
-void DefaultUserWallpaperDelegate::UpdateWallpaper() {
+void DefaultUserWallpaperDelegate::UpdateWallpaper(bool clear_cache) {
 }
 
 void DefaultUserWallpaperDelegate::InitializeWallpaper() {
   ash::Shell::GetInstance()->desktop_background_controller()->
       CreateEmptyWallpaper();
 }
 
 void DefaultUserWallpaperDelegate::OpenSetWallpaperPage() {
 }
 
 bool DefaultUserWallpaperDelegate::CanOpenSetWallpaperPage() {
   return false;
 }
 
 void DefaultUserWallpaperDelegate::OnWallpaperAnimationFinished() {
 }
 
 void DefaultUserWallpaperDelegate::OnWallpaperBootAnimationFinished() {
 }
 
 }  // namespace ash