Make ExtensionTtsPlatformImplWin a leaky singleton to avoid a crash in the destructor.

chrome/browser/speech/extension_api/tts_extension_api_platform.h

 // Copyright (c) 2012 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_SPEECH_EXTENSION_API_TTS_EXTENSION_API_PLATFORM_H_
 #define CHROME_BROWSER_SPEECH_EXTENSION_API_TTS_EXTENSION_API_PLATFORM_H_
 #pragma once
 
 #include <string>
 
@@ skipping 35 matching lines @@
   // Return the gender of the voice, should be either "male" or "female"
   // if known, otherwise the empty string.
   virtual std::string gender();
 
   virtual std::string error();
   virtual void clear_error();
   virtual void set_error(const std::string& error);
 
  protected:
   ExtensionTtsPlatformImpl() {}
+
+  // On some platforms this may be a leaky singleton - do not rely on the
+  // destructor being called!  http://crbug.com/122026
   virtual ~ExtensionTtsPlatformImpl() {}
 
   std::string error_;
 
   DISALLOW_COPY_AND_ASSIGN(ExtensionTtsPlatformImpl);
 };
 
 #endif  // CHROME_BROWSER_SPEECH_EXTENSION_API_TTS_EXTENSION_API_PLATFORM_H_