[NTP] Fix article suggestion clicks contributing to Most Visited tiles

components/history/core/browser/history_types.h

 // Copyright 2014 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_HISTORY_CORE_BROWSER_HISTORY_TYPES_H_
 #define COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_TYPES_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 314 matching lines @@
   GURL url;
   base::string16 title;
 
   // If this is a URL for which we want to force a thumbnail, records the last
   // time it was forced so we can evict it when more recent URLs are requested.
   // If it's not a forced thumbnail, keep a time of 0.
   base::Time last_forced_time;
 
   RedirectList redirects;
 
-  bool operator==(const MostVisitedURL& other) {
+  bool operator==(const MostVisitedURL& other) const {
     return url == other.url;
   }
 };
 
 // FilteredURL -----------------------------------------------------------------
 
 // Holds the per-URL information of the filterd url query.
 struct FilteredURL {
   struct ExtendedInfo {
     ExtendedInfo();
@@ skipping 202 matching lines @@
   void SetTimeRangeForOneDay(base::Time time);
 
   std::set<GURL> urls;
   base::Time begin_time;
   base::Time end_time;
 };
 
 }  // namespace history
 
 #endif  // COMPONENTS_HISTORY_CORE_BROWSER_HISTORY_TYPES_H_