Expose always-on hotword preference via hotwordPrivate API.

chrome/test/data/extensions/api_test/hotword_private/alwaysOnEnabled/test.js

Index: chrome/test/data/extensions/api_test/hotword_private/alwaysOnEnabled/test.js
diff --git a/chrome/test/data/extensions/api_test/hotword_private/isAvailable/test.js b/chrome/test/data/extensions/api_test/hotword_private/alwaysOnEnabled/test.js
similarity index 72%
copy from chrome/test/data/extensions/api_test/hotword_private/isAvailable/test.js
copy to chrome/test/data/extensions/api_test/hotword_private/alwaysOnEnabled/test.js
index 01ef5b831bdf78a537d8199de612f683ac0bd265..97f6973e215dd9b3175086cf5f3cc134e2afb2ec 100644
--- a/chrome/test/data/extensions/api_test/hotword_private/isAvailable/test.js
+++ b/chrome/test/data/extensions/api_test/hotword_private/alwaysOnEnabled/test.js
@@ -3,10 +3,10 @@
 // found in the LICENSE file.
 
 chrome.test.runTests([
-  function isAvailable() {
+  function alwaysOnEnabled() {
     chrome.hotwordPrivate.getStatus(
         chrome.test.callbackPass(function(result) {
-          chrome.test.sendMessage("available: " + result.available);
+          chrome.test.sendMessage("alwaysOnEnabled: " + result.alwaysOnEnabled);
     }));
   }
 ]);