Virtual destructors should have virtual keyword.

chrome/browser/extensions/extension_tts_api.h

Index: chrome/browser/extensions/extension_tts_api.h
diff --git a/chrome/browser/extensions/extension_tts_api.h b/chrome/browser/extensions/extension_tts_api.h
index ad436a85fed9f4ca277fd057c02c4406f6f3ff06..88e8ba8477e7405fc734376c9df19325d82e8c51 100644
--- a/chrome/browser/extensions/extension_tts_api.h
+++ b/chrome/browser/extensions/extension_tts_api.h
@@ -205,7 +205,7 @@ class ExtensionTtsController {
 
 class ExtensionTtsSpeakFunction : public AsyncExtensionFunction {
  private:
-  ~ExtensionTtsSpeakFunction() {}
+  virtual ~ExtensionTtsSpeakFunction() {}
   virtual bool RunImpl();
   void SpeechFinished();
   Utterance* utterance_;
@@ -214,21 +214,21 @@ class ExtensionTtsSpeakFunction : public AsyncExtensionFunction {
 
 class ExtensionTtsStopSpeakingFunction : public SyncExtensionFunction {
  private:
-  ~ExtensionTtsStopSpeakingFunction() {}
+  virtual ~ExtensionTtsStopSpeakingFunction() {}
   virtual bool RunImpl();
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.tts.stop")
 };
 
 class ExtensionTtsIsSpeakingFunction : public SyncExtensionFunction {
  private:
-  ~ExtensionTtsIsSpeakingFunction() {}
+  virtual ~ExtensionTtsIsSpeakingFunction() {}
   virtual bool RunImpl();
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.tts.isSpeaking")
 };
 
 class ExtensionTtsSpeakCompletedFunction : public SyncExtensionFunction {
  private:
-  ~ExtensionTtsSpeakCompletedFunction() {}
+  virtual ~ExtensionTtsSpeakCompletedFunction() {}
   virtual bool RunImpl();
   DECLARE_EXTENSION_FUNCTION_NAME("experimental.tts.speakCompleted")
 };