Revert of Delete "shutdown without closing browsers" path

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 <string>
 
 #include "ash/ash_export.h"
@@ skipping 58 matching lines @@
   // Incognito windows are restricted for supervised users.
   virtual bool IsIncognitoAllowed() const = 0;
 
   // Returns true if we're running in forced app mode.
   virtual bool IsRunningInForcedAppMode() const = 0;
 
   // Called before processing |Shell::Init()| so that the delegate
   // can perform tasks necessary before the shell is initialized.
   virtual void PreInit() = 0;
 
-  // Called at the beginninig of Shell destructor so that
-  // delegate can use Shell instance to perform cleanup tasks.
-  virtual void PreShutdown() = 0;
+  // Shuts down the environment.
+  virtual void Shutdown() = 0;
 
   // Invoked when the user uses Ctrl-Shift-Q to close chrome.
   virtual void Exit() = 0;
 
   // Create a shell-specific keyboard::KeyboardControllerProxy
   virtual keyboard::KeyboardControllerProxy*
       CreateKeyboardControllerProxy() = 0;
 
   // Get the active browser context. This will get us the active profile
   // in chrome.
@@ skipping 40 matching lines @@
   // Creates a GPU support object. Shell takes ownership of the object.
   virtual GPUSupport* CreateGPUSupport() = 0;
 
   // Get the product name.
   virtual base::string16 GetProductName() const = 0;
 };
 
 }  // namespace ash
 
 #endif  // ASH_SHELL_DELEGATE_H_