Hotword Private API: Add function and event to query the existence of a speaker model

chrome/browser/search/hotword_service.h

Index: chrome/browser/search/hotword_service.h
diff --git a/chrome/browser/search/hotword_service.h b/chrome/browser/search/hotword_service.h
index 2c0e086ba12c99f80ae2c522cc5e681ecea7649f..e5da97433f0fc3124784c1dbd5f49daa42909cb4 100644
--- a/chrome/browser/search/hotword_service.h
+++ b/chrome/browser/search/hotword_service.h
@@ -146,9 +146,15 @@ class HotwordService : public extensions::ExtensionRegistryObserver,
     HOTWORD_AND_AUDIO_HISTORY,
     RETRAIN
   };
+  void OptIntoHotwording(const LaunchMode& launch_mode);
   void LaunchHotwordAudioVerificationApp(const LaunchMode& launch_mode);
   virtual LaunchMode GetHotwordAudioVerificationLaunchMode();
 
+  // Called when the SpeakerModelExists request is complete. Either
+  // sets the always-on hotword pref to true, or launches the Hotword
+  // Audio Verification App, depending on the value of |exists|.
+  void SpeakerModelExistsComplete(bool exists);
+
   // These methods control the speaker training communication between
   // the Hotword Audio Verification App and the Hotword Extension that
   // contains the NaCl module.