Switch SupportsUserData uses to use unique_ptr.

ios/chrome/browser/infobars/infobar_manager_impl.h

 // Copyright 2014 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_CHROME_BROWSER_INFOBARS_INFOBAR_MANAGER_IMPL_H_
 #define IOS_CHROME_BROWSER_INFOBARS_INFOBAR_MANAGER_IMPL_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "components/infobars/core/infobar_manager.h"
 #include "ios/web/public/web_state/web_state_observer.h"
 #include "ios/web/public/web_state/web_state_user_data.h"
 
 namespace infobars {
 class InfoBar;
 }
 
 namespace web {
 struct LoadCommittedDetails;
 class WebState;
 }
 
 // Associates a Tab to an InfoBarManager and manages its lifetime.
 // It responds to navigation events.
 class InfoBarManagerImpl : public infobars::InfoBarManager,
                            public web::WebStateObserver,
                            public web::WebStateUserData<InfoBarManagerImpl> {
  public:
+  ~InfoBarManagerImpl() override;
+
   // This function must only be called on infobars that are owned by an
   // InfoBarManagerImpl instance (or not owned at all, in which case this
   // returns null).
   static web::WebState* WebStateFromInfoBar(infobars::InfoBar* infobar);
 
  private:
   friend class web::WebStateUserData<InfoBarManagerImpl>;
 
   explicit InfoBarManagerImpl(web::WebState* web_state);
-  ~InfoBarManagerImpl() override;
 
   // InfoBarManager implementation.
   int GetActiveEntryID() override;
   std::unique_ptr<infobars::InfoBar> CreateConfirmInfoBar(
       std::unique_ptr<ConfirmInfoBarDelegate> delegate) override;
 
   // web::WebStateObserver implementation.
   void NavigationItemCommitted(
       const web::LoadCommittedDetails& load_details) override;
   void WebStateDestroyed() override;
 
   // Opens a URL according to the specified |disposition|.
   void OpenURL(const GURL& url, WindowOpenDisposition disposition) override;
 
   DISALLOW_COPY_AND_ASSIGN(InfoBarManagerImpl);
 };
 
 #endif  // IOS_CHROME_BROWSER_INFOBARS_INFOBAR_MANAGER_IMPL_H_