Notify hotwording extension of microphone state change.

chrome/browser/resources/hotword/manager.js

Index: chrome/browser/resources/hotword/manager.js
diff --git a/chrome/browser/resources/hotword/manager.js b/chrome/browser/resources/hotword/manager.js
index d186a3f424b2ef9d7dc615277487fce700c69553..bfcabd89eae86d7edf8bf0ce623bb8bc7a6737d5 100644
--- a/chrome/browser/resources/hotword/manager.js
+++ b/chrome/browser/resources/hotword/manager.js
@@ -44,6 +44,16 @@
     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) {