[Aura] Refactor and update app list window.

chrome/browser/ui/views/aura/chrome_shell_delegate.cc

 // Copyright (c) 2011 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 "chrome/browser/ui/views/aura/chrome_shell_delegate.h"
 
 #include "chrome/browser/profiles/profile_manager.h"
 #include "chrome/browser/ui/browser.h"
 #include "chrome/browser/ui/views/aura/app_list_window.h"
 #include "chrome/browser/ui/views/aura/status_area_host_aura.h"
@@ skipping 39 matching lines @@
   browser->window()->Show();
 }
 
 views::Widget* ChromeShellDelegate::CreateStatusArea() {
   status_area_host_.reset(new StatusAreaHostAura());
   views::Widget* status_area_widget =
       status_area_host_.get()->CreateStatusArea();
   return status_area_widget;
 }
 
-void ChromeShellDelegate::ShowApps() {
-  AppListWindow::SetVisible(!AppListWindow::IsVisible());
+void ChromeShellDelegate::RequestAppListWidget(
+    const SetWidgetCallback& callback) {
+  new AppListWindow(callback);  // AppListWindow deletes itself when closed.
 }
 
 void ChromeShellDelegate::LauncherItemClicked(
     const aura_shell::LauncherItem& item) {
   item.window->Activate();
 }
 
 bool ChromeShellDelegate::ConfigureLauncherItem(
     aura_shell::LauncherItem* item) {
   BrowserView* view = BrowserView::GetBrowserViewForNativeWindow(item->window);
   return view &&
       ShouldCreateLauncherItemForBrowser(view->browser(), &(item->type));
 }