Notify hotwording extension of microphone state change.

chrome/browser/resources/hotword/manager.js

 // Copyright 2014 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.
 
 (function() {
   'use strict';
 
   /**
    * @fileoverview This extension provides hotword triggering capabilites to
    * Chrome.
@@ skipping 26 matching lines @@
   // Detect a request to delete the speaker model.
   chrome.hotwordPrivate.onDeleteSpeakerModel.addListener(function() {
     hotword.TrainingManager.handleDeleteSpeakerModel();
   });
 
   // Detect a request for the speaker model existence.
   chrome.hotwordPrivate.onSpeakerModelExists.addListener(function() {
     hotword.TrainingManager.handleSpeakerModelExists();
   });
 
+  // Detect the microphone state has changed.
+  chrome.hotwordPrivate.onMicrophoneStateChanged.addListener(function(enabled) {

[kcarattini, 2015/03/31 23:31:46]

How about making the PageAudioManager listen for this event directly? Then you
can setup and remove the listener according to whether sometimes-on is enabled.

[calamity, 2015/04/01 02:36:10]

Good point. It also means I'm not calling private methods here -.-

+    if (enabled) {
+      pageAudioManager.updateTabState_();
+      return;
+    }
+
+    pageAudioManager.stopHotwording_();
+  });
+
   // Detect when the shared module containing the NaCL module and language model
   // is installed.
   chrome.management.onInstalled.addListener(function(info) {
     if (info.id == hotword.constants.SHARED_MODULE_ID) {
       hotword.debug('Shared module installed, reloading extension.');
       chrome.runtime.reload();
     }
   });
 }());