Disable tracking of visits to bookmarks in incognito

chrome/browser/ntp_snippets/bookmark_last_visit_updater.h

 // Copyright 2016 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_NTP_SNIPPETS_BOOKMARK_LAST_VISIT_UPDATER_H_
 #define CHROME_BROWSER_NTP_SNIPPETS_BOOKMARK_LAST_VISIT_UPDATER_H_
 
 #include <memory>
 #include <set>
 
@@ skipping 14 matching lines @@
 
 // A bridge class between platform-specific content::WebContentsObserver and the
 // generic function ntp_snippets::UpdateBookmarkOnURLVisitedInMainFrame().
 class BookmarkLastVisitUpdater
     : public content::WebContentsObserver,
       public content::WebContentsUserData<BookmarkLastVisitUpdater>,
       public bookmarks::BookmarkModelObserver {
  public:
   ~BookmarkLastVisitUpdater() override;
 
-  static void CreateForWebContentsWithBookmarkModel(
+  static void MaybeCreateForWebContentsWithBookmarkModel(
       content::WebContents* web_contents,
       bookmarks::BookmarkModel* bookmark_model);
 
  private:
   friend class content::WebContentsUserData<BookmarkLastVisitUpdater>;
 
   BookmarkLastVisitUpdater(content::WebContents* web_contents,
                            bookmarks::BookmarkModel* bookmark_model);
 
   // Overridden from BookmarkModelObserver:
@@ skipping 33 matching lines @@
 
   void NewURLVisited(content::NavigationHandle* navigation_handle);
 
   bookmarks::BookmarkModel* bookmark_model_;
   content::WebContents* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(BookmarkLastVisitUpdater);
 };
 
 #endif  // CHROME_BROWSER_NTP_SNIPPETS_BOOKMARK_LAST_VISIT_UPDATER_H_