Add Pause and Resume to Web TTS & Extension TTS APIs

chrome/browser/speech/tts_controller.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_TTS_CONTROLLER_H_
 #define CHROME_BROWSER_SPEECH_TTS_CONTROLLER_H_
 
 #include <queue>
 #include <set>
 #include <string>
@@ skipping 13 matching lines @@
 
 // Events sent back from the TTS engine indicating the progress.
 enum TtsEventType {
   TTS_EVENT_START,
   TTS_EVENT_END,
   TTS_EVENT_WORD,
   TTS_EVENT_SENTENCE,
   TTS_EVENT_MARKER,
   TTS_EVENT_INTERRUPTED,
   TTS_EVENT_CANCELLED,
-  TTS_EVENT_ERROR
+  TTS_EVENT_ERROR,
+  TTS_EVENT_PAUSE,
+  TTS_EVENT_RESUME
 };
 
 enum TtsGenderType {
   TTS_GENDER_NONE,
   TTS_GENDER_MALE,
   TTS_GENDER_FEMALE
 };
 
 // Returns true if this event type is one that indicates an utterance
 // is finished and can be destroyed.
@@ skipping 191 matching lines @@
 
   // Returns true if we're currently speaking an utterance.
   bool IsSpeaking();
 
   // Speak the given utterance. If the utterance's can_enqueue flag is true
   // and another utterance is in progress, adds it to the end of the queue.
   // Otherwise, interrupts any current utterance and speaks this one
   // immediately.
   void SpeakOrEnqueue(Utterance* utterance);
 
-  // Stop all utterances and flush the queue.
+  // Stop all utterances and flush the queue. Implies leaving pause mode
+  // as well.
   void Stop();
 
+  // Pause the speech queue. Some engines may support pausing in the middle
+  // of an utterance.
+  void Pause();
+
+  // Resume speaking.
+  void Resume();
+
   // Handle events received from the speech engine. Events are forwarded to
   // the callback function, and in addition, completion and error events
   // trigger finishing the current utterance and starting the next one, if
   // any.
   void OnTtsEvent(int utterance_id,
                   TtsEventType event_type,
                   int char_index,
                   const std::string& error_message);
 
   // Return a list of all available voices, including the native voice,
@@ skipping 33 matching lines @@
   // Given an utterance and a vector of voices, return the
   // index of the voice that best matches the utterance.
   int GetMatchingVoice(const Utterance* utterance,
                        std::vector<VoiceData>& voices);
 
   friend struct DefaultSingletonTraits<TtsController>;
 
   // The current utterance being spoken.
   Utterance* current_utterance_;
 
+  // Whether the queue is paused or not.
+  bool paused_;
+
   // A queue of utterances to speak after the current one finishes.
   std::queue<Utterance*> utterance_queue_;
 
   // A pointer to the platform implementation of text-to-speech, for
   // dependency injection.
   TtsPlatformImpl* platform_impl_;
 
   DISALLOW_COPY_AND_ASSIGN(TtsController);
 };
 
 #endif  // CHROME_BROWSER_SPEECH_TTS_CONTROLLER_H_