Polished UI for the host side of pairing flow.

chrome/browser/resources/chromeos/login/oobe-screen.js

+// Copyright (c) 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.
+
+Polymer('oobe-screen', (function() {
+  /** @const */ var CALLBACK_USER_ACTED = 'userActed';
+
+  function doNothing() {};
+
+  return {
+    /**
+     * The login.Screen which is hosting |this|.
+     */
+    screen_: null,
+
+    /**
+     * Dictionary of context observers that are methods of |this| bound to
+     * |this|.
+     */
+    contextObservers_: null,
+
+    /**
+     * login.ScreenContext used for sharing data with native backend.
+     */
+    context: null,
+
+    /**
+     * Internal storage of |this.context|. Short name has been choosen for
+     * reason: such name doesn't take much space in HTML data bindings, which
+     * are used very often.
+     * C binded to the native part of the context, that means that all the
+     * changes in the native part appear in C automticaly. Reverse is not true,
+     * you should use:
+     *    this.context.set(...);
+     *    this.context.commitContextChanges();
+     * to send updates to the native part.
+     * TODO(dzhioev): make binding two-way.
+     */
+    C: null,
+
+    /**
+     * Called when the screen is beeing registered.
+     */
+    initialize: doNothing,
+
+    ready: function() {
+      if (this.decorate_) {
+        this.initialize();
+      } else {
+        this.ready_ = true;
+      }
+    },
+
+    i18n: function(args) {
+      if (!(args instanceof Array))
+        args = [args];
+      args[0] = 'login_' + this.name + '_' + args[0];
+      return loadTimeData.getStringF.apply(loadTimeData, args);
+    },
+
+    /**
+     * Called by login.Screen when the screen is beeing registered.
+     */
+    decorate: function(screen) {
+      this.screen_ = screen;
+      screen.initialize();
+      this.context = screen.screenContext_;
+      this.C = this.context.storage_;
+      this.contextObservers_ = {};
+      var self = this;
+      this.querySelectorAllImpl_('button[action]').forEach(function(button) {
+        button.addEventListener('click', function(e) {
+          var action = this.getAttribute('action');
+          self.send(CALLBACK_USER_ACTED, action);
+          e.stopPropagation();
+        });
+      });
+      if (this.ready_) {
+        this.initialize();
+      } else {
+        this.decorate_ = true;
+      }
+    },
+
+    /**
+     * @final
+     */
+    send: function() {
+      return this.sendImpl_.apply(this, arguments);
+    },
+
+    /**
+     * @final
+     */
+    addContextObserver: function() {
+      return this.addContextObserverImpl_.apply(this, arguments);
+    },
+
+    /**
+     * @final
+     */
+    removeContextObserver: function() {
+      return this.removeContextObserverImpl_.apply(this, arguments);
+    },
+
+    /**
+     * @final
+     */
+    commitContextChanges: function() {
+      return this.commitContextChangesImpl_.apply(this, arguments);
+    },
+
+    /**
+     * @override
+     * @final
+     */
+    querySelector: function() {
+      return this.querySelectorImpl_.apply(this, arguments);
+    },
+
+    /**
+     * @override
+     * @final
+     */
+    querySelectorAll: function() {
+      return this.querySelectorAllImpl_.apply(this, arguments);
+    },
+
+    /**
+     * See login.Screen.send.
+     * @private
+     */
+    sendImpl_: function() {
+      return this.screen_.send.apply(this.screen_, arguments);
+    },
+
+    /**
+     * Starts observation of property with |key| of the context attached to
+     * current screen. This method differs from "login.ScreenContext" in that
+     * it automatically detects if observer is method of |this| and make
+     * all needed actions to make it work correctly. So it's no need for client
+     * to bind methods to |this| and keep resulting callback for
+     * |removeObserver| call:
+     *
+     *   this.addContextObserver('key', this.onKeyChanged_);
+     *   ...
+     *   this.removeContextObserver('key', this.onKeyChanged_);
+     * @private
+     */
+    addContextObserverImpl_: function(key, observer) {
+      var realObserver = observer;
+      var propertyName = this.getPropertyNameOf_(observer);
+      if (propertyName) {
+        if (!this.contextObservers_.hasOwnProperty(propertyName))
+          this.contextObservers_[propertyName] = observer.bind(this);
+        realObserver = this.contextObservers_[propertyName];
+      }
+      this.context.addObserver(key, realObserver);
+    },
+
+    /**
+     * Removes |observer| from the list of context observers. Supports not only
+     * regular functions but also screen methods (see comment to
+     * |addContextObserver|).
+     * @private
+     */
+    removeContextObserverImpl_: function(observer) {
+      var realObserver = observer;
+      var propertyName = this.getPropertyNameOf_(observer);
+      if (propertyName) {
+        if (!this.contextObservers_.hasOwnProperty(propertyName))
+          return;
+        realObserver = this.contextObservers_[propertyName];
+        delete this.contextObservers_[propertyName];
+      }
+      this.context.removeObserver(realObserver);
+    },
+
+    /**
+     * See login.Screen.commitContextChanges.
+     * @private
+     */
+    commitContextChangesImpl_: function() {
+      return this.screen_.commitContextChanges.apply(this.screen_, arguments);
+    },
+
+    /**
+     * Calls |querySelector| method of the shadow dom and returns the result.
+     * @private
+     */
+    querySelectorImpl_: function(selector) {
+      return this.shadowRoot.querySelector(selector);
+    },
+
+
+    /**
+     * Calls standart |querySelectorAll| method of the shadow dom and returns
+     * the result converted to Array.
+     * @private
+     */
+    querySelectorAllImpl_: function(selector) {
+      var list = this.shadowRoot.querySelectorAll(selector);
+      return Array.prototype.slice.call(list);
+    },
+
+    /**
+     * If |value| is the value of some property of |this| returns property's
+     * name. Otherwise returns empty string.
+     * @private
+     */
+    getPropertyNameOf_: function(value) {
+      for (var key in this)
+        if (this[key] === value)
+          return key;
+      return '';
+    }
+  };
+})());
+