Import Chrome's tts code

chromium_src/chrome/browser/speech/tts_platform.h

@@ -0,0 +1,81 @@
+// 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_TTS_PLATFORM_H_
+#define CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_
+
+#include <string>
+
+#include "chrome/browser/speech/tts_controller.h"
+
+// Abstract class that defines the native platform TTS interface,
+// subclassed by specific implementations on Win, Mac, etc.
+class TtsPlatformImpl {
+ public:
+  static TtsPlatformImpl* GetInstance();
+
+  // Returns true if this platform implementation is supported and available.
+  virtual bool PlatformImplAvailable() = 0;
+
+  // Some platforms may provide a built-in TTS extension. Returns true
+  // if the extension was not previously loaded and is now loading, and
+  // false if it's already loaded or if there's no extension to load.
+  // Will call TtsController::RetrySpeakingQueuedUtterances when
+  // the extension finishes loading.
+  virtual bool LoadBuiltInTtsExtension(
+      content::BrowserContext* browser_context);
+
+  // Speak the given utterance with the given parameters if possible,
+  // and return true on success. Utterance will always be nonempty.
+  // If rate, pitch, or volume are -1.0, they will be ignored.
+  //
+  // The TtsController will only try to speak one utterance at
+  // a time. If it wants to interrupt speech, it will always call Stop
+  // before speaking again.
+  virtual bool Speak(
+      int utterance_id,
+      const std::string& utterance,
+      const std::string& lang,
+      const VoiceData& voice,
+      const UtteranceContinuousParameters& params) = 0;
+
+  // Stop speaking immediately and return true on success.
+  virtual bool StopSpeaking() = 0;
+
+  // Returns whether any speech is on going.
+  virtual bool IsSpeaking() = 0;
+
+  // Append information about voices provided by this platform implementation
+  // to |out_voices|.
+  virtual void GetVoices(std::vector<VoiceData>* out_voices) = 0;
+
+  // Pause the current utterance, if any, until a call to Resume,
+  // Speak, or StopSpeaking.
+  virtual void Pause() = 0;
+
+  // Resume speaking the current utterance, if it was paused.
+  virtual void Resume() = 0;
+
+  // Allows the platform to monitor speech commands and the voices used
+  // for each one.
+  virtual void WillSpeakUtteranceWithVoice(const Utterance* utterance,
+                                           const VoiceData& voice_data);
+
+  virtual std::string error();
+  virtual void clear_error();
+  virtual void set_error(const std::string& error);
+
+ protected:
+  TtsPlatformImpl() {}
+
+  // On some platforms this may be a leaky singleton - do not rely on the
+  // destructor being called!  http://crbug.com/122026
+  virtual ~TtsPlatformImpl() {}
+
+  std::string error_;
+
+  DISALLOW_COPY_AND_ASSIGN(TtsPlatformImpl);
+};
+
+#endif  // CHROME_BROWSER_SPEECH_TTS_PLATFORM_H_