Added InitTts function to speech synthesis library

chrome/browser/chromeos/cros/speech_synthesis_library.h

Index: chrome/browser/chromeos/cros/speech_synthesis_library.h
===================================================================
--- chrome/browser/chromeos/cros/speech_synthesis_library.h	(revision 49185)
+++ chrome/browser/chromeos/cros/speech_synthesis_library.h	(working copy)
@@ -12,6 +12,8 @@
 // This interface defines the interaction with the ChromeOS login library APIs.
 class SpeechSynthesisLibrary {
  public:
+  typedef void(*InitStatusCallback)(bool success);
+
   virtual ~SpeechSynthesisLibrary() {}
   // Speaks the specified text.
   virtual bool Speak(const char* text) = 0;
@@ -21,6 +23,9 @@
   virtual bool StopSpeaking() = 0;
   // Checks if the engine is currently speaking.
   virtual bool IsSpeaking() = 0;
+  // Starts the speech synthesis service and indicates through a callback if
+  // it started successfully.
+  virtual void InitTts(InitStatusCallback) = 0;
 };
 
 // This class handles the interaction with the ChromeOS login library APIs.
@@ -34,6 +39,7 @@
   virtual bool SetSpeakProperties(const char* props);
   virtual bool StopSpeaking();
   virtual bool IsSpeaking();
+  virtual void InitTts(InitStatusCallback);
 
  private:
   DISALLOW_COPY_AND_ASSIGN(SpeechSynthesisLibraryImpl);