Remove now obsolete Shutdown method of ChromeBrowserStateManager.

ios/public/provider/chrome/browser/browser_state/chrome_browser_state_manager.h

 // Copyright 2013 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 IOS_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_MANAGER_H_
 #define IOS_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_MANAGER_H_
 
 #include <vector>
 
 #include "base/compiler_specific.h"
 #include "base/macros.h"
 
 namespace base {
 class FilePath;
 }
 
 class BrowserStateInfoCache;
 
 namespace ios {
 
 class ChromeBrowserState;
 
 // Provides methods that allow for various ways of creating non-incognito
 // ChromeBrowserState instances. Owns all instances that it creates.
 class ChromeBrowserStateManager {
  public:
   virtual ~ChromeBrowserStateManager() {}
 
-  // Temporary method to help migrating from ProfileManager to
-  // ChromeBrowserStateManager.
-  virtual void ShutDown() {}
-
   // Returns the ChromeBrowserState that was last used, creating one if
   // necessary.
   virtual ChromeBrowserState* GetLastUsedBrowserState() = 0;
 
   // Returns the ChromeBrowserState associated with |path|, creating one if
   // necessary.
   virtual ChromeBrowserState* GetBrowserState(const base::FilePath& path) = 0;
 
   // Returns the BrowserStateInfoCache associated with this manager.
   virtual BrowserStateInfoCache* GetBrowserStateInfoCache() = 0;
 
   // Returns the list of loaded ChromeBrowserStates.
   virtual std::vector<ChromeBrowserState*> GetLoadedBrowserStates() = 0;
 
  protected:
   ChromeBrowserStateManager() {}
 
  private:
   DISALLOW_COPY_AND_ASSIGN(ChromeBrowserStateManager);
 };
 
 }  // namespace ios
 
 #endif  // IOS_PUBLIC_PROVIDER_CHROME_BROWSER_BROWSER_STATE_CHROME_BROWSER_STATE_MANAGER_H_