Use bookmark creation date fallback for 6 weeks after installing M54

components/ntp_snippets/bookmarks/bookmark_last_visit_utils.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 COMPONENTS_NTP_SNIPPETS_BOOKMARKS_BOOKMARK_LAST_VISIT_UTILS_H_
 #define COMPONENTS_NTP_SNIPPETS_BOOKMARKS_BOOKMARK_LAST_VISIT_UTILS_H_
 
 #include <vector>
 
 class GURL;
@@ skipping 13 matching lines @@
 // to now. If there are multiple bookmarks for a given URL, it updates all of
 // them.
 void UpdateBookmarkOnURLVisitedInMainFrame(
     bookmarks::BookmarkModel* bookmark_model,
     const GURL& url);
 
 // Gets the last visit date for a given bookmark |node|. The visit when the
 // bookmark is created also counts. If no info about last visit date is present
 // and |creation_date_fallback| is true, creation date is used.
 base::Time GetLastVisitDateForBookmark(const bookmarks::BookmarkNode* node,
-                                       bool creation_date_fallback = true);
+                                       bool creation_date_fallback);
 
 // Like GetLastVisitDateForBookmark, but it returns the unix epoch if the
 // bookmark is dismissed from NTP.
 base::Time GetLastVisitDateForBookmarkIfNotDismissed(
     const bookmarks::BookmarkNode* node,
-    bool creation_date_fallback = true);
+    bool creation_date_fallback);
 
 // Marks all bookmarks with the given URL as dismissed.
 void MarkBookmarksDismissed(bookmarks::BookmarkModel* bookmark_model,
                             const GURL& url);
 
 // Gets the dismissed flag for a given bookmark |node|. Defaults to false.
 bool IsDismissedFromNTPForBookmark(const bookmarks::BookmarkNode* node);
 
 // Removes the dismissed flag from all bookmarks (only for debugging).
 void MarkAllBookmarksUndismissed(bookmarks::BookmarkModel* bookmark_model);
@@ skipping 10 matching lines @@
     int max_count,
     const base::Time& min_visit_time);
 
 // Returns the list of all dismissed bookmarks. Only used for debugging.
 std::vector<const bookmarks::BookmarkNode*> GetDismissedBookmarksForDebugging(
     bookmarks::BookmarkModel* bookmark_model);
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_BOOKMARKS_BOOKMARK_LAST_VISIT_UTILS_H_