Virtual destructors should have virtual keyword.

chrome/browser/autocomplete/history_quick_provider.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_AUTOCOMPLETE_HISTORY_QUICK_PROVIDER_H_
 #define CHROME_BROWSER_AUTOCOMPLETE_HISTORY_QUICK_PROVIDER_H_
 #pragma once
 
 #include <string>
 
@@ skipping 10 matching lines @@
 }  // namespace history
 
 // This class is an autocomplete provider (a pseudo-internal component of
 // the history system) which quickly (and synchronously) provides matching
 // results from recently or frequently visited sites in the profile's
 // history.
 class HistoryQuickProvider : public HistoryProvider {
  public:
   HistoryQuickProvider(ACProviderListener* listener, Profile* profile);
 
-  ~HistoryQuickProvider();
+  virtual ~HistoryQuickProvider();
 
   // AutocompleteProvider. |minimal_changes| is ignored since there
   // is no asynch completion performed.
   virtual void Start(const AutocompleteInput& input,
                      bool minimal_changes) OVERRIDE;
 
   virtual void DeleteMatch(const AutocompleteMatch& match) OVERRIDE;
 
   // Performs the autocomplete matching and scoring.
   void DoAutocomplete();
@@ skipping 32 matching lines @@
   // Only for use in unittests.  Takes ownership of |index|.
   void SetIndexForTesting(history::InMemoryURLIndex* index);
   AutocompleteInput autocomplete_input_;
   std::string languages_;
 
   // Only used for testing.
   scoped_ptr<history::InMemoryURLIndex> index_for_testing_;
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_QUICK_PROVIDER_H_