Update SupportsUserData uses with unique_ptr.

chrome/browser/banners/app_banner_manager_desktop.h

 // Copyright 2015 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 CHROME_BROWSER_BANNERS_APP_BANNER_MANAGER_DESKTOP_H_
 #define CHROME_BROWSER_BANNERS_APP_BANNER_MANAGER_DESKTOP_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "chrome/browser/banners/app_banner_manager.h"
 #include "content/public/browser/web_contents_user_data.h"
 
 namespace extensions {
 class BookmarkAppHelper;
 }
 
 namespace banners {
 
 // Manages web app banners for desktop platforms.
 class AppBannerManagerDesktop
     : public AppBannerManager,
       public content::WebContentsUserData<AppBannerManagerDesktop> {
  public:
+  ~AppBannerManagerDesktop() override;
+
   static bool IsEnabled();
 
  private:
   friend class content::WebContentsUserData<AppBannerManagerDesktop>;
 
   explicit AppBannerManagerDesktop(content::WebContents* web_contents);
-  ~AppBannerManagerDesktop() override;
 
   // AppBannerManager overrides.
   void DidFinishCreatingBookmarkApp(
       const extensions::Extension* extension,
       const WebApplicationInfo& web_app_info) override;
   bool IsWebAppInstalled(content::BrowserContext* browser_context,
                          const GURL& start_url,
                          const GURL& manifest_url) override;
   void ShowBanner() override;
 
   // content::WebContentsObserver override.
   void DidFinishLoad(content::RenderFrameHost* render_frame_host,
                      const GURL& validated_url) override;
 
   // SiteEngagementObserver override.
   void OnEngagementIncreased(content::WebContents* web_contents,
                              const GURL& url,
                              double score) override;
 
   std::unique_ptr<extensions::BookmarkAppHelper> bookmark_app_helper_;
 
   DISALLOW_COPY_AND_ASSIGN(AppBannerManagerDesktop);
 };
 
 }  // namespace banners
 
 #endif  // CHROME_BROWSER_BANNERS_APP_BANNER_MANAGER_DESKTOP_H_