cros: Allow user to configure note taking app in md-settings.

chrome/browser/resources/settings/device_page/stylus.js

 // Copyright 2016 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.
 
 /**
  * @fileoverview
  * 'settings-stylus' is the settings subpage with stylus-specific settings.
  */
 
+/** @const */ var FIND_MORE_APPS_URL = 'https://play.google.com/store/apps/' +
+    'collection/promotion_30023cb_stylus_apps';
+
 Polymer({
   is: 'settings-stylus',
 
   properties: {
     /** Preferences state. */
     prefs: {
       type: Object,
       notify: true,
     },
-  }
+
+    /**
+     * Note taking apps the user can pick between.
+     * @type {Array<{name:string, value:string, preferred:boolean}>}
+     * @private
+     */
+    appChoices_: {
+      type: Array,
+      value: function() { return []; }
+    },
+
+    /**
+     * True if the ARC container has not finished starting yet.
+     * @private
+     */
+    waitingForAndroid_: {
+      type: Boolean,
+      value: false
+    },
+  },
+
+
+  /** @private {?settings.DevicePageBrowserProxy} */
+  browserProxy_: null,
+
+  created: function() {
+    this.browserProxy_ = settings.DevicePageBrowserProxyImpl.getInstance();
+  },
+
+  ready: function() {
+    this.browserProxy_.setNoteTakingAppsUpdatedCallback(
+        this.onNoteAppsUpdated_.bind(this));
+    this.browserProxy_.requestNoteTakingApps();
+  },
+
+  /** @private */
+  onSelectedAppChanged_: function() {
+    this.browserProxy_.setPreferredNoteTakingApp(this.$.menu.value);
+  },
+
+  /**
+   * @param {Array<settings.NoteAppInfo>} apps
+   * @param {boolean} waitingForAndroid
+   * @private
+   */
+  onNoteAppsUpdated_: function(apps, waitingForAndroid) {
+    this.waitingForAndroid_ = waitingForAndroid;
+    this.appChoices_ = apps;
+  },
+
+  /**
+   * @param {Array<settings.NoteAppInfo>} apps
+   * @param {boolean} waitingForAndroid
+   * @private
+   */
+  showNoApps_: function(apps, waitingForAndroid) {
+    return apps.length == 0 && !waitingForAndroid;
+  },
+
+  /**
+   * @param {Array<settings.NoteAppInfo>} apps
+   * @param {boolean} waitingForAndroid
+   * @private
+   */
+  showApps_: function(apps, waitingForAndroid) {
+    return apps.length > 0 && !waitingForAndroid;
+  },
+
+  /** @private */
+  onFindAppsTap_: function() {
+    window.open(FIND_MORE_APPS_URL);
+  },
 });