Adding speech synthesis library to access TTS feature in libcros.

chrome/browser/chromeos/cros/speech_synthesis_library.h

+// Copyright (c) 2010 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_CROS_SPEECH_SYNTHESIS_LIBRARY_H_
+#define CHROME_BROWSER_CHROMEOS_CROS_SPEECH_SYNTHESIS_LIBRARY_H_
+
+#include "base/singleton.h"
+
+namespace chromeos {
+
+// This interface defines the interaction with the ChromeOS login library APIs.
+class SpeechSynthesisLibrary {
+ public:
+  virtual ~SpeechSynthesisLibrary() {}
+  // Speaks the specified text.
+  virtual bool Speak(const char* text) = 0;
+  // Sets options for the subsequent speech synthesis requests.
+  virtual bool SetSpeakProperties(const char* props) = 0;
+  // Stops speaking the current utterance.
+  virtual bool StopSpeaking() = 0;
+  // Checks if the engine is currently speaking.
+  virtual bool IsSpeaking() = 0;
+};
+
+// This class handles the interaction with the ChromeOS login library APIs.
+class SpeechSynthesisLibraryImpl : public SpeechSynthesisLibrary {
+ public:
+  SpeechSynthesisLibraryImpl() {}
+  virtual ~SpeechSynthesisLibraryImpl() {}
+
+  // SpeechSynthesisLibrary overrides.
+  virtual bool Speak(const char* text);
+  virtual bool SetSpeakProperties(const char* props);
+  virtual bool StopSpeaking();
+  virtual bool IsSpeaking();
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(SpeechSynthesisLibraryImpl);
+};
+
+}  // namespace chromeos
+
+#endif  // CHROME_BROWSER_CHROMEOS_CROS_SPEECH_SYNTHESIS_LIBRARY_H_