Forget about DesktopBackgroundWidget if it was deleted

ash/desktop_background/desktop_background_view.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_view.h"
 
 #include <limits>
 
 #include "ash/ash_export.h"
 #include "ash/desktop_background/desktop_background_controller.h"
 #include "ash/desktop_background/desktop_background_widget_controller.h"
 #include "ash/shell.h"
 #include "ash/shell_window_ids.h"
 #include "ash/wm/window_animations.h"
 #include "base/message_loop.h"
 #include "base/utf_string_conversions.h"
 #include "grit/ui_resources.h"
 #include "ui/aura/root_window.h"
 #include "ui/base/resource/resource_bundle.h"
 #include "ui/compositor/layer.h"
 #include "ui/compositor/layer_animation_observer.h"
 #include "ui/compositor/scoped_layer_animation_settings.h"
 #include "ui/gfx/canvas.h"
 #include "ui/gfx/image/image.h"
 #include "ui/views/widget/widget.h"
+#include "ui/views/widget/widget_delegate.h"
 
 namespace ash {
 namespace internal {
 namespace {
 
+class DesktopBackgroundViewCleanup : public views::WidgetDelegate {
+ public:
+  DesktopBackgroundViewCleanup(views::Widget* widget,
+                               aura::RootWindow* root_window)
+      : widget_(widget_),
+        root_window_(root_window) {
+  }
+
+  // Called when the window closes. The delegate MUST NOT delete itself during
+  // this call, since it can be called afterwards. See DeleteDelegate().
+  virtual void WindowClosing() OVERRIDE  {
+    DesktopBackgroundController* controller = ash::Shell::GetInstance()->
+        desktop_background_controller();
+    controller->CleanupView(root_window_);
+  }
+
+  virtual const views::Widget* GetWidget() OVERRIDE const {
+    return widget_;
+  }
+
+  virtual views::Widget* GetWidget() OVERRIDE {
+    return widget_;
+  }
+
+  virtual void DeleteDelegate() OVERRIDE {
+    delete this;
+  }
+
+ private:
+  views::Widget* widget_;
+  aura::RootWindow* root_window_;
+
+  DISALLOW_COPY_AND_ASSIGN(DesktopBackgroundViewCleanup);
+};
+
 class ShowWallpaperAnimationObserver : public ui::ImplicitAnimationObserver {
  public:
   ShowWallpaperAnimationObserver(aura::RootWindow* root_window,
                                  int container_id,
                                  views::Widget* desktop_widget)
       : root_window_(root_window),
         container_id_(container_id),
         desktop_widget_(desktop_widget) {
   }
 
@@ skipping 101 matching lines @@
 void DesktopBackgroundView::ShowContextMenuForView(views::View* source,
                                                    const gfx::Point& point) {
   Shell::GetInstance()->ShowBackgroundMenu(GetWidget(), point);
 }
 
 views::Widget* CreateDesktopBackground(aura::RootWindow* root_window,
                                        int container_id) {
   DesktopBackgroundController* controller = ash::Shell::GetInstance()->
       desktop_background_controller();
   views::Widget* desktop_widget = new views::Widget;
+  DesktopBackgroundViewCleanup* cleanup;
+  cleanup = new DesktopBackgroundViewCleanup(desktop_widget, root_window);
   views::Widget::InitParams params(
       views::Widget::InitParams::TYPE_WINDOW_FRAMELESS);
   DesktopBackgroundView* view = new DesktopBackgroundView();
   params.delegate = view;
   if (controller->GetWallpaper().isNull())
     params.transparent = true;
+  params.delegate = cleanup;
   params.parent = root_window->GetChildById(container_id);
   desktop_widget->Init(params);
   desktop_widget->SetContentsView(view);
   ash::WindowVisibilityAnimationType animation_type =
       ash::Shell::GetInstance()->user_wallpaper_delegate()->GetAnimationType();
   ash::SetWindowVisibilityAnimationType(desktop_widget->GetNativeView(),
                                         animation_type);
   // Disable animation when creating the first widget. Otherwise, wallpaper
   // will animate from a white screen. Note that boot animation is different.
   // It animates from a white background.
@@ skipping 12 matching lines @@
   settings.AddObserver(new ShowWallpaperAnimationObserver(root_window,
                                                           container_id,
                                                           desktop_widget));
   desktop_widget->Show();
   desktop_widget->GetNativeView()->SetName("DesktopBackgroundView");
   return desktop_widget;
 }
 
 }  // namespace internal
 }  // namespace ash