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

chrome/browser/ntp_snippets/ntp_bookmark_helper.cc

Index: chrome/browser/ntp_snippets/ntp_bookmark_helper.cc
diff --git a/chrome/browser/ntp_snippets/ntp_bookmark_helper.cc b/chrome/browser/ntp_snippets/ntp_bookmark_helper.cc
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+// Copyright (c) 2012 The Chromium Authors. All rights reserved.

[Marc Treib, 2016/07/29 09:54:56]

Also here

[jkrcal, 2016/07/29 12:42:41]

Done.

+// 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/ntp_bookmark_helper.h"
+
+#include "components/bookmarks/browser/bookmark_model.h"
+#include "components/ntp_snippets/bookmarks/bookmark_last_visit_date_helper.h"
+#include "content/public/browser/navigation_handle.h"
+
+DEFINE_WEB_CONTENTS_USER_DATA_KEY(ntp_snippets::NTPBookmarkHelper);
+
+namespace ntp_snippets {
+
+// static
+void NTPBookmarkHelper::CreateForWebContentsWithBookmarkModel(
+    content::WebContents* web_contents,
+    BookmarkModel* bookmark_model) {
+  DCHECK(web_contents);
+  web_contents->SetUserData(
+      UserDataKey(), new NTPBookmarkHelper(web_contents, bookmark_model));
+}
+
+NTPBookmarkHelper::~NTPBookmarkHelper() {}
+
+NTPBookmarkHelper::NTPBookmarkHelper(
+    content::WebContents* web_contents,
+    BookmarkModel* bookmark_model)
+    : content::WebContentsObserver(web_contents),
+      bookmark_model_(bookmark_model),
+      navigation_observer_(new BookmarkLastVisitDateHelper) {}
+
+void NTPBookmarkHelper::DidStartNavigation(
+    content::NavigationHandle* navigation_handle) {
+  if (!navigation_handle->IsInMainFrame() || navigation_handle->IsErrorPage())
+    return;
+  navigation_observer_->OnURLVisitedInMainFrame(bookmark_model_,
+                                                navigation_handle->GetURL());
+}
+
+}  // namespace ntp_snippets