Add a StateManager for managing hotwording state based on various factors

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.
 
-'use strict';
+(function() {
+  'use strict';
 
-/**
- * @fileoverview This extension provides hotword triggering capabilites to
- * Chrome.
- *
- * This extension contains all the JavaScript for loading and managing the
- * hotword detector. The hotword detector and language model data will be
- * provided by a shared module loaded from the web store.
- */
+  /**
+   * @fileoverview This extension provides hotword triggering capabilites to
+   * Chrome.
+   *
+   * This extension contains all the JavaScript for loading and managing the
+   * hotword detector. The hotword detector and language model data will be
+   * provided by a shared module loaded from the web store.
+   *
+   * IMPORTANT! Whenever adding new events, the extension version number MUST be
+   * incremented.
+   */
 
+  // Hotwording state.
+  var stateManager = new hotword.StateManager();
+
+  // Detect Chrome startup and make sure we get a chance to run.
+  chrome.runtime.onStartup.addListener(function() {
+    stateManager.updateStatus();
+  });
+
+  // Detect when hotword settings have changed.
+  chrome.hotwordPrivate.onEnabledChanged.addListener(function() {
+    stateManager.updateStatus();
+  });
+
+  // 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)
+      chrome.runtime.reload();
+  });
+
+  // Detect when a session has requested to be started and stopped.
+  chrome.hotwordPrivate.onHotwordSessionRequested.addListener(function() {
+    // TODO(amistry): This event should change state depending on whether the
+    // user has enabled always-on hotwording. But for now, always signal the
+    // start of a hotwording session. This allows this extension to work with
+    // the app launcher in the current state.
+    chrome.hotwordPrivate.setHotwordSessionState(true, function() {});
+  });
+
+  chrome.hotwordPrivate.onHotwordSessionStopped.addListener(function() {
+    chrome.hotwordPrivate.setHotwordSessionState(false, function() {});
+  });
+}());