Virtual destructors should have virtual keyword.

content/browser/speech/speech_recognizer.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 CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_
 #define CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_
 
 #include <list>
 #include <string>
 #include <utility>
@@ skipping 66 matching lines @@
    protected:
     virtual ~Delegate() {}
   };
 
   SpeechRecognizer(Delegate* delegate,
                    int caller_id,
                    const std::string& language,
                    const std::string& grammar,
                    const std::string& hardware_info,
                    const std::string& origin_url);
-  ~SpeechRecognizer();
+  virtual ~SpeechRecognizer();
 
   // Starts audio recording and does recognition after recording ends. The same
   // SpeechRecognizer instance can be used multiple times for speech recognition
   // though each recognition request can be made only after the previous one
   // completes (i.e. after receiving Delegate::DidCompleteRecognition).
   bool StartRecording();
 
   // Stops recording audio and starts recognition.
   void StopRecording();
 
@@ skipping 49 matching lines @@
 
 // This typedef is to workaround the issue with certain versions of
 // Visual Studio where it gets confused between multiple Delegate
 // classes and gives a C2500 error. (I saw this error on the try bots -
 // the workaround was not needed for my machine).
 typedef SpeechRecognizer::Delegate SpeechRecognizerDelegate;
 
 }  // namespace speech_input
 
 #endif  // CONTENT_BROWSER_SPEECH_SPEECH_RECOGNIZER_H_