chromeos: Add a stub implementation for SensorsSource.

chrome/browser/chromeos/dbus/speech_synthesizer_client.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 CHROME_BROWSER_CHROMEOS_DBUS_SPEECH_SYNTHESIZER_CLIENT_H_
 #define CHROME_BROWSER_CHROMEOS_DBUS_SPEECH_SYNTHESIZER_CLIENT_H_
 #pragma once
 
 #include <string>
 
 #include "base/callback.h"
 
 namespace dbus {
 class Bus;
 }
 
 namespace chromeos {
 
 // SpeechSynthesizerClient is used to communicate with the speech synthesizer.
 // All method should be called from the origin thread (UI thread) which
 // initializes the DBusThreadManager instance.
 class SpeechSynthesizerClient {
  public:
   // A callback function called when the result of IsSpeaking is ready.
   // The argument indicates if the speech synthesizer is speaking or not.
   typedef base::Callback<void(bool)> IsSpeakingCallback;
 
-  virtual ~SpeechSynthesizerClient() {}
+  virtual ~SpeechSynthesizerClient();
 
   // Speaks the specified text.
   virtual void Speak(const std::string& text) = 0;
 
   // Sets options for the subsequent speech synthesis requests.
   // Use the constants below.
   virtual void SetSpeakProperties(const std::string& props) = 0;
 
   // Stops speaking the current utterance.
   virtual void StopSpeaking() = 0;
 
   // Checks if the engine is currently speaking.
   // |callback| will be called on the origin thread later with the result.
   virtual void IsSpeaking(IsSpeakingCallback callback) = 0;
 
   // Factory function, creates a new instance and returns ownership.
   // For normal usage, access the singleton via DBusThreadManager::Get().
   static SpeechSynthesizerClient* Create(dbus::Bus* bus);
 
   // Constants to be used with SetSpeakProperties.
   static const char kSpeechPropertyLocale[];
   static const char kSpeechPropertyGender[];
   static const char kSpeechPropertyRate[];
   static const char kSpeechPropertyPitch[];
   static const char kSpeechPropertyVolume[];
   static const char kSpeechPropertyEquals[];
   static const char kSpeechPropertyDelimiter[];
+
+ protected:
+  // Create() should be used instead.
+  SpeechSynthesizerClient();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SpeechSynthesizerClient);
 };
 
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_DBUS_SPEECH_SYNTHESIZER_CLIENT_H_