[Extensions] Convert some SyncExtensionFunctions

chrome/browser/speech/extension_api/tts_engine_extension_api.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_ENGINE_EXTENSION_API_H_
 #define CHROME_BROWSER_SPEECH_EXTENSION_API_TTS_ENGINE_EXTENSION_API_H_
 
 #include <vector>
 
 #include "base/memory/singleton.h"
@@ skipping 31 matching lines @@
                  std::vector<VoiceData>* out_voices) override;
   void Speak(Utterance* utterance, const VoiceData& voice) override;
   void Stop(Utterance* utterance) override;
   void Pause(Utterance* utterance) override;
   void Resume(Utterance* utterance) override;
   bool LoadBuiltInTtsExtension(
       content::BrowserContext* browser_context) override;
 };
 // Hidden/internal extension function used to allow TTS engine extensions
 // to send events back to the client that's calling tts.speak().
-class ExtensionTtsEngineSendTtsEventFunction : public SyncExtensionFunction {
+class ExtensionTtsEngineSendTtsEventFunction
+    : public UIThreadExtensionFunction {
  private:
   ~ExtensionTtsEngineSendTtsEventFunction() override {}
-  bool RunSync() override;
+  ResponseAction Run() override;
   DECLARE_EXTENSION_FUNCTION("ttsEngine.sendTtsEvent", TTSENGINE_SENDTTSEVENT)
 };
 
 #endif  // CHROME_BROWSER_SPEECH_EXTENSION_API_TTS_ENGINE_EXTENSION_API_H_