Rename ash desktop_background to wallpaper.

ash/wm/system_background_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/wm/system_background_controller.h"
-
-#include "ui/aura/window.h"
-#include "ui/compositor/layer.h"
-#include "ui/compositor/layer_type.h"
-
-namespace ash {
-
-SystemBackgroundController::SystemBackgroundController(
-    aura::Window* root_window,
-    SkColor color)
-    : root_window_(root_window), layer_(new ui::Layer(ui::LAYER_SOLID_COLOR)) {
-  root_window_->AddObserver(this);
-  layer_->SetColor(color);
-
-  ui::Layer* root_layer = root_window_->layer();
-  layer_->SetBounds(gfx::Rect(root_layer->bounds().size()));
-  root_layer->Add(layer_.get());
-  root_layer->StackAtBottom(layer_.get());
-}
-
-SystemBackgroundController::~SystemBackgroundController() {
-  root_window_->RemoveObserver(this);
-}
-
-void SystemBackgroundController::SetColor(SkColor color) {
-  layer_->SetColor(color);
-}
-
-void SystemBackgroundController::OnWindowBoundsChanged(
-    aura::Window* root,
-    const gfx::Rect& old_bounds,
-    const gfx::Rect& new_bounds) {
-  DCHECK_EQ(root_window_, root);
-  layer_->SetBounds(gfx::Rect(root_window_->layer()->bounds().size()));
-}
-
-}  // namespace ash