Virtual destructors should have virtual keyword.

chrome/browser/history/history_types.h

 // Copyright (c) 2011 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 CHROME_BROWSER_HISTORY_HISTORY_TYPES_H_
 #define CHROME_BROWSER_HISTORY_HISTORY_TYPES_H_
 #pragma once
 
 #include <deque>
 #include <map>
@@ skipping 327 matching lines @@
 
 // URLResult -------------------------------------------------------------------
 
 class URLResult : public URLRow {
  public:
   URLResult();
   URLResult(const GURL& url, base::Time visit_time);
   // Constructor that create a URLResult from the specified URL and title match
   // positions from title_matches.
   URLResult(const GURL& url, const Snippet::MatchPositions& title_matches);
-  ~URLResult();
+  virtual ~URLResult();
 
   base::Time visit_time() const { return visit_time_; }
   void set_visit_time(base::Time visit_time) { visit_time_ = visit_time; }
 
   const Snippet& snippet() const { return snippet_; }
 
   // If this is a title match, title_match_positions contains an entry for
   // every word in the title that matched one of the query parameters. Each
   // entry contains the start and end of the match.
   const Snippet::MatchPositions& title_match_positions() const {
@@ skipping 376 matching lines @@
   // The icon's URL.
   GURL icon_url;
 
   // The type of favicon.
   history::IconType icon_type;
 };
 
 }  // namespace history
 
 #endif  // CHROME_BROWSER_HISTORY_HISTORY_TYPES_H_