Cancel the JumpList update if top 5 most visited URLs are unchanged

chrome/browser/win/jumplist_update_util.cc

Index: chrome/browser/win/jumplist_update_util.cc
diff --git a/chrome/browser/win/jumplist_update_util.cc b/chrome/browser/win/jumplist_update_util.cc
new file mode 100644
index 0000000000000000000000000000000000000000..c8a8a25f6d8319b4e7cfbf0e905559ae26466196
--- /dev/null
+++ b/chrome/browser/win/jumplist_update_util.cc
@@ -0,0 +1,26 @@
+// Copyright (c) 2017 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/win/jumplist_update_util.h"
+
+#include <algorithm>
+#include <iterator>
+
+bool MostVisitedItemsUnchanged(const ShellLinkItemList& items,
+                               const history::MostVisitedURLList& urls,
+                               size_t max_item_count) {
+  // If the number of urls going to be displayed doesn't equal to the current
+  // one, the most visited items are considered to have changes.
+  // Otherwise, check if the current urls stored in |items| equal to the first
+  // |max_item_count| urls in |urls| to determine if the most visited items
+  // are changed or not.
+
+  if (std::min(urls.size(), max_item_count) != items.size())
+    return false;
+
+  return std::equal(std::begin(items), std::end(items), std::begin(urls),
+                    [](const auto& item_ptr, const auto& most_visited_url) {
+                      return item_ptr->url() == most_visited_url.url.spec();
+                    });
+}