Add Pause and Resume to Web TTS & Extension TTS APIs

chrome/browser/speech/tts_controller.h

Index: chrome/browser/speech/tts_controller.h
diff --git a/chrome/browser/speech/tts_controller.h b/chrome/browser/speech/tts_controller.h
index b6b7372a645b9ca2d1c1bba57ba16da7cf383d39..b55600aa06df417a2146d4232b928c4574ab064e 100644
--- a/chrome/browser/speech/tts_controller.h
+++ b/chrome/browser/speech/tts_controller.h
@@ -31,7 +31,9 @@ enum TtsEventType {
   TTS_EVENT_MARKER,
   TTS_EVENT_INTERRUPTED,
   TTS_EVENT_CANCELLED,
-  TTS_EVENT_ERROR
+  TTS_EVENT_ERROR,
+  TTS_EVENT_PAUSE,
+  TTS_EVENT_RESUME
 };
 
 enum TtsGenderType {
@@ -251,9 +253,17 @@ class TtsController {
   // 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
@@ -317,6 +327,9 @@ class 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_;