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

chrome/browser/ntp_snippets/bookmark_last_visit_updater.cc

+// 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.
+
+#include "chrome/browser/ntp_snippets/bookmark_last_visit_updater.h"
+
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "components/ntp_snippets/bookmarks/bookmark_last_visit_utils.h"
+#include "content/public/browser/navigation_handle.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(BookmarkLastVisitUpdater);
+
+// static
+void BookmarkLastVisitUpdater::CreateForWebContentsWithBookmarkModel(

[sky, 2016/08/01 15:15:47]

nit: make order match header.

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

Done.

+    content::WebContents* web_contents,
+    bookmarks::BookmarkModel* bookmark_model) {
+  DCHECK(web_contents);
+  web_contents->SetUserData(UserDataKey(), new BookmarkLastVisitUpdater(
+                                               web_contents, bookmark_model));
+}
+
+BookmarkLastVisitUpdater::~BookmarkLastVisitUpdater() {}
+
+BookmarkLastVisitUpdater::BookmarkLastVisitUpdater(
+    content::WebContents* web_contents,
+    bookmarks::BookmarkModel* bookmark_model)
+    : content::WebContentsObserver(web_contents),
+      bookmark_model_(bookmark_model) {}
+
+void BookmarkLastVisitUpdater::DidStartNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (!navigation_handle->IsInMainFrame() || navigation_handle->IsErrorPage())
+    return;
+  ntp_snippets::UpdateBookmarkOnURLVisitedInMainFrame(
+      bookmark_model_, navigation_handle->GetURL());
+}