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

ash/shell.cc

Index: ash/shell.cc
diff --git a/ash/shell.cc b/ash/shell.cc
index 1e8742a688abc0a75e6a0f5ef52c94a3ba66fcab..a66d0d7ff7a64f096b6bdf10ef54e47d695e623a 100644
--- a/ash/shell.cc
+++ b/ash/shell.cc
@@ -8,6 +8,9 @@
 
 #include "ash/app_list/app_list.h"
 #include "ash/ash_switches.h"
+#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/drag_drop/drag_drop_controller.h"
 #include "ash/focus_cycler.h"
 #include "ash/ime/input_method_event_filter.h"
@@ -475,6 +478,9 @@ void Shell::Init() {
       GetContainer(internal::kShellWindowId_DefaultContainer);
   launcher_.reset(new Launcher(default_container));
 
+  // This controller needs to be set before SetupManagedWindowMode.
+  desktop_background_controller_.reset(new DesktopBackgroundController);
+
   InitLayoutManagers();
 
   if (!command_line->HasSwitch(switches::kAuraNoShadows))
@@ -538,25 +544,35 @@ void Shell::ToggleAppList() {
   app_list_->SetVisible(!app_list_->IsVisible());
 }
 
-void Shell::SetDesktopBackgroundMode(BackgroundMode mode) {
-  if (mode == BACKGROUND_SOLID_COLOR) {
-    // 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
-    ui::Layer* background_layer = new ui::Layer(ui::Layer::LAYER_SOLID_COLOR);
-    background_layer->SetColor(SK_ColorBLACK);
-    GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->
-        layer()->Add(background_layer);
-    root_window_layout_->SetBackgroundLayer(background_layer);
-    root_window_layout_->SetBackgroundWidget(NULL);
-  } else {
-    // Create the desktop background image.
-    root_window_layout_->SetBackgroundLayer(NULL);
-    root_window_layout_->SetBackgroundWidget(
-        internal::CreateDesktopBackground());
-  }
-  desktop_background_mode_ = mode;
+void Shell::SetDesktopBackgroundWallpaper(const SkBitmap& wallpaper) {
+  if (desktop_background_mode_ == BACKGROUND_SOLID_COLOR)
+    return;
+
+  DCHECK(root_window_layout_->background_widget());
+  static_cast<internal::DesktopBackgroundView*>(
+      root_window_layout_->background_widget()->widget_delegate())->
+      SetWallpaper(wallpaper);
+}
+
+void Shell::SetDesktopBackgroundImageMode(const SkBitmap& wallpaper) {
+  root_window_layout_->SetBackgroundLayer(NULL);
+  root_window_layout_->SetBackgroundWidget(
+      internal::CreateDesktopBackground(wallpaper));
+  desktop_background_mode_ = BACKGROUND_IMAGE;
+}
+
+void Shell::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
+  ui::Layer* background_layer = new ui::Layer(ui::Layer::LAYER_SOLID_COLOR);
+  background_layer->SetColor(SK_ColorBLACK);
+  GetContainer(internal::kShellWindowId_DesktopBackgroundContainer)->
+      layer()->Add(background_layer);
+  root_window_layout_->SetBackgroundLayer(background_layer);
+  root_window_layout_->SetBackgroundWidget(NULL);
+  desktop_background_mode_ = BACKGROUND_SOLID_COLOR;
 }
 
 bool Shell::IsScreenLocked() const {
@@ -618,7 +634,8 @@ void Shell::InitLayoutManagers() {
   launcher_->widget()->Show();
 
   // Create the desktop background image.
-  SetDesktopBackgroundMode(BACKGROUND_IMAGE);
+  SetDesktopBackgroundImageMode(desktop_background_controller_->
+                                    GetPresetWallpaper());
 }
 
 void Shell::DisableWorkspaceGridLayout() {