Enable user change background image in settings page in Aura build.

ash/desktop_background/desktop_background_controller.cc

Index: ash/desktop_background/desktop_background_controller.cc
diff --git a/ash/desktop_background/desktop_background_controller.cc b/ash/desktop_background/desktop_background_controller.cc
new file mode 100644
index 0000000000000000000000000000000000000000..cc4e017179742f972520b9ba361e3e3c960803ca
--- /dev/null
+++ b/ash/desktop_background/desktop_background_controller.cc
@@ -0,0 +1,77 @@
+// 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_controller.h"
+
+#include "ash/desktop_background/desktop_background_resources.h"
+#include "ash/desktop_background/desktop_background_view.h"
+#include "ash/shell.h"
+#include "ash/shell_factory.h"
+#include "ash/shell_window_ids.h"
+#include "ash/wm/root_window_layout_manager.h"
+#include "base/logging.h"
+#include "grit/ui_resources.h"
+#include "ui/aura/window.h"
+#include "ui/gfx/compositor/layer.h"
+#include "ui/gfx/image/image.h"
+#include "ui/base/resource/resource_bundle.h"
+#include "ui/views/widget/widget.h"
+
+namespace ash {
+
+DesktopBackgroundController::DesktopBackgroundController() :
+  previous_wallpaper_index_(GetDefaultWallpaperIndex()),
+  desktop_background_mode_(BACKGROUND_IMAGE) {
+}
+
+DesktopBackgroundController::~DesktopBackgroundController() {
+}
+
+void DesktopBackgroundController::OnDesktopBackgroundChanged(int index) {
+  internal::RootWindowLayoutManager* root_window_layout =
+      Shell::GetInstance()->root_window_layout();
+  if (desktop_background_mode_ == BACKGROUND_SOLID_COLOR)
+    return;
+
+  DCHECK(root_window_layout->background_widget()->widget_delegate());
+  static_cast<internal::DesktopBackgroundView*>(
+      root_window_layout->background_widget()->widget_delegate())->
+          SetWallpaper(GetWallpaper(index));
+  previous_wallpaper_index_ = index;
+}
+
+void DesktopBackgroundController::SetDesktopBackgroundImageMode(
+    const SkBitmap& wallpaper) {
+  internal::RootWindowLayoutManager* root_window_layout =
+      Shell::GetInstance()->root_window_layout();
+  root_window_layout->SetBackgroundLayer(NULL);
+  root_window_layout->SetBackgroundWidget(
+      internal::CreateDesktopBackground(wallpaper));
+  desktop_background_mode_ = BACKGROUND_IMAGE;
+}
+
+void DesktopBackgroundController::SetDefaultDesktopBackgroundImage() {
+  SetDesktopBackgroundImageMode(GetWallpaper(GetDefaultWallpaperIndex()));
+}
+
+void DesktopBackgroundController::SetPreviousDesktopBackgroundImage() {
+  SetDesktopBackgroundImageMode(GetWallpaper(previous_wallpaper_index_));
+}
+
+void DesktopBackgroundController::SetDesktopBackgroundSolidColorMode() {
+  // Set a solid black background.
+  // TODO(derat): Remove this in favor of having the compositor only clear the
+  // viewport when there are regions not covered by a layer:
+  // http://crbug.com/113445
+  Shell* shell = Shell::GetInstance();
+  ui::Layer* background_layer = new ui::Layer(ui::Layer::LAYER_SOLID_COLOR);
+  background_layer->SetColor(SK_ColorBLACK);
+  shell->GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->
+      layer()->Add(background_layer);
+  shell->root_window_layout()->SetBackgroundLayer(background_layer);
+  shell->root_window_layout()->SetBackgroundWidget(NULL);
+  desktop_background_mode_ = BACKGROUND_SOLID_COLOR;
+}
+
+}  // namespace ash