Add the "virtual" keyword on method overrides that are missing it.

chrome/browser/autocomplete/history_quick_provider.h

 // Copyright (c) 2010 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 15 matching lines @@
 // TODO(mrossetti): Review to see if the following applies since we're not
 // using the database during the autocomplete pass.
 class HistoryQuickProvider : public HistoryProvider {
  public:
   HistoryQuickProvider(ACProviderListener* listener, Profile* profile);
 
   ~HistoryQuickProvider();
 
   // AutocompleteProvider. |minimal_changes| is ignored since there
   // is no asynch completion performed.
-  void Start(const AutocompleteInput& input, bool minimal_changes);
+  virtual void Start(const AutocompleteInput& input, bool minimal_changes);
 
   // Performs the autocomplete matching and scoring.
   void DoAutocomplete();
 
  private:
   friend class HistoryQuickProviderTest;
 
   AutocompleteMatch QuickMatchToACMatch(
       const history::ScoredHistoryMatch& history_match,
       MatchType match_type,
@@ skipping 20 matching lines @@
   void SetIndexForTesting(history::InMemoryURLIndex* index);
   AutocompleteInput autocomplete_input_;
   bool trim_http_;
   std::string languages_;
 
   // Only used for testing.
   scoped_ptr<history::InMemoryURLIndex> index_for_testing_;
 };
 
 #endif  // CHROME_BROWSER_AUTOCOMPLETE_HISTORY_QUICK_PROVIDER_H_