[Aura] Implement views-based applist.

ui/aura_shell/shell_delegate.h

 // 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.
 
 #ifndef UI_AURA_SHELL_SHELL_DELEGATE_H_
 #define UI_AURA_SHELL_SHELL_DELEGATE_H_
 #pragma once
 
 #include "base/callback.h"
 #include "ui/aura_shell/aura_shell_export.h"
 
 namespace gfx {
 class Rect;
 }
 
 namespace views {
 class Widget;
 }
 
 namespace aura_shell {
 
+class AppListModel;
+class AppListViewDelegate;
 struct LauncherItem;
 
 // Delegate of the Shell.
 class AURA_SHELL_EXPORT ShellDelegate {
  public:
   // Callback to pass back a widget used by RequestAppListWidget.
   typedef base::Callback<void(views::Widget*)> SetWidgetCallback;
 
   // The Shell owns the delegate.
   virtual ~ShellDelegate() {}
 
   // Invoked when the user clicks on button in the launcher to create a new
   // window.
   virtual void CreateNewWindow() = 0;
 
   // Invoked to create a new status area. Can return NULL.
   virtual views::Widget* CreateStatusArea() = 0;
 
   // Invoked to create app list widget. The Delegate calls the callback
   // when the widget is ready to show.
+  // Deprecated.
+  // TODO(xiyuan): Clean this up when switching to views app list.
   virtual void RequestAppListWidget(
       const gfx::Rect& bounds,
       const SetWidgetCallback& callback) = 0;
 
+  // Invoked to ask the delegate to populate the |model|.
+  virtual void BuildAppListModel(AppListModel* model) = 0;
+
+  // Invoked to create an AppListViewDelegate. Shell takes the ownership of
+  // the created delegate.
+  virtual AppListViewDelegate* CreateAppListViewDelegate() = 0;
+
   // Invoked when the user clicks on a window entry in the launcher.
   virtual void LauncherItemClicked(const LauncherItem& item) = 0;
 
   // Invoked when a window is added. If the delegate wants the launcher to show
   // an entry for |item->window| it should configure |item| appropriately and
   // return true.
   virtual bool ConfigureLauncherItem(LauncherItem* item) = 0;
 };
 }  // namespace aura_shell
 
 #endif  // UI_AURA_SHELL_SHELL_DELEGATE_H_