[WIP] ash/extensions: Add experimental extension support for window-management in ash.

ash/shell_delegate.h

 // 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.
 
 #ifndef ASH_SHELL_DELEGATE_H_
 #define ASH_SHELL_DELEGATE_H_
 
 #include <vector>
 
 #include "ash/ash_export.h"
@@ skipping 17 matching lines @@
 }
 
 namespace ash {
 
 class LauncherDelegate;
 class LauncherModel;
 struct LauncherItem;
 class SystemTray;
 class SystemTrayDelegate;
 class UserWallpaperDelegate;
+class WindowManagerExtensionDelegate;
 
 enum UserMetricsAction {
   UMA_ACCEL_NEWTAB_T,
   UMA_ACCEL_NEXTWINDOW_F5,
   UMA_ACCEL_NEXTWINDOW_TAB,
   UMA_ACCEL_PREVWINDOW_F5,
   UMA_ACCEL_PREVWINDOW_TAB,
   UMA_ACCEL_SEARCH_LWIN,
   UMA_LAUNCHER_CLICK_ON_APP,
   UMA_LAUNCHER_CLICK_ON_APPLIST_BUTTON,
@@ skipping 77 matching lines @@
 
   // Creates a system-tray delegate. Shell takes ownership of the delegate.
   virtual SystemTrayDelegate* CreateSystemTrayDelegate(SystemTray* tray) = 0;
 
   // Creates a user wallpaper delegate. Shell takes ownership of the delegate.
   virtual UserWallpaperDelegate* CreateUserWallpaperDelegate() = 0;
 
   // Creates a user action client. Shell takes ownership of the object.
   virtual aura::client::UserActionClient* CreateUserActionClient() = 0;
 
+  virtual ash::WindowManagerExtensionDelegate*
+      CreateWindowManagerDelegate() = 0;
+
   // Opens the feedback page for "Report Issue".
   virtual void OpenFeedbackPage() = 0;
 
   // Records that the user performed an action.
   virtual void RecordUserMetricsAction(UserMetricsAction action) = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_DELEGATE_H_