Add a tab helper to record the last visit date for each bookmark.

components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h

Index: components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h
diff --git a/components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h b/components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h
new file mode 100644
index 0000000000000000000000000000000000000000..660b473cd1193a7bfc086ea40f2d9845ec5abb13
--- /dev/null
+++ b/components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h
@@ -0,0 +1,41 @@
+// 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 <memory>
+#include <vector>
+
+#include "base/macros.h"
+#include "base/time/time.h"
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "components/bookmarks/browser/bookmark_node.h"
+
+namespace ntp_snippets {
+
+// If there is a bookmark for |url|, this function updates its last visit date
+// 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|. If the bookmark lacks
+// this info, it returns it creation date.
+base::Time GetLastVisitDateForBookmark(
+    const bookmarks::BookmarkNode* node);
+
+// Returns the list of most recently visited bookmarked URLs. For each such URL

[Marc Treib, 2016/07/30 14:38:09]

nit: It really returns the bookmarks, not just the bookmarked URLs.

[Philipp Keck, 2016/08/02 13:05:33]

Done.

+// it returns the most recently created bookmark. The result is ordered by visit
+// time (the most recent first). Only bookmarked URLs visited after
+// |min_visit_time| are considered, at most |max_count| bookmarks are returned.
+std::vector<const bookmarks::BookmarkNode*> GetRecentlyVisitedBookmarks(
+    bookmarks::BookmarkModel* bookmark_model,
+    int max_count,
+    const base::Time& min_visit_time);
+
+}  // namespace ntp_snippets
+
+#endif  // COMPONENTS_NTP_SNIPPETS_BOOKMARKS_BOOKMARK_LAST_VISIT_UTILS_H_