Show MessageWindow from the background page

remoting/webapp/background/message_window.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';
+
+/**
+ * @constructor
+ */
+function MessageWindowImpl() {
+  /**
+   * Used to prevent multiple responses due to the closeWindow handler.
+   *
+   * @type {boolean}
+   * @private
+   */
+  this.sentReply_ = false;
+
+  window.addEventListener('message', this.onMessage_.bind(this), false);
+};
+
+/**
+ * @param {Window} parentWindow The id of the window that showed the message.
+ * @param {string} messageId The identifier of the message, as supplied by the
+ *     parent.
+ * @param {number} result 0 if window was closed without pressing a button;
+ *     otherwise the index of the button pressed (e.g., 1 = primary).
+ * @private
+ */
+MessageWindowImpl.prototype.sendReply_ = function(
+    parentWindow, messageId, result) {
+  // Only forward the first reply that we receive.
+  if (!this.sentReply_) {
+    var message = {
+      command: 'messageWindowResult',
+      id: messageId,
+      result: result
+    };
+    parentWindow.postMessage(message, '*');
+    this.sentReply_ = true;
+  } else {
+    // Make sure that the reply we're ignoring is from the window close.
+    base.debug.assert(result == 0);
+  }
+};
+
+/**
+ * Size the window to its content vertically.
+ * @private
+ */
+MessageWindowImpl.prototype.updateSize_ = function() {
+  var borderY = window.outerHeight - window.innerHeight;
+  window.resizeTo(window.outerWidth, document.body.clientHeight + borderY);
+};
+
+/**
+ * Initializes the button with the label and the click handler.
+ * Hides the button if the label is null or undefined.
+ *
+ * @param{HTMLElement} button
+ * @param{?string} label
+ * @param{Function} clickHandler
+ * @private
+ */
+MessageWindowImpl.prototype.initButton_ =
+    function(button, label, clickHandler) {
+  if (label) {
+    button.innerText = label;
+    button.addEventListener('click', clickHandler, false);
+  }
+  button.hidden = !Boolean(label);
+};
+
+/**
+ * Event-handler callback, invoked when the parent window supplies the
+ * message content.
+ *
+ * @param{Event} event
+ * @private
+ */
+MessageWindowImpl.prototype.onMessage_ = function(event) {
+  switch (event.data['command']) {
+    case 'show':
+      // Validate the message.
+      var messageId = /** @type {number} */ (event.data['id']);
+      var title = /** @type {string} */ (event.data['title']);
+      var message = /** @type {string} */ (event.data['message']);
+      var infobox = /** @type {string} */ (event.data['infobox']);
+      var buttonLabel = /** @type {string} */ (event.data['buttonLabel']);
+      /** @type {string} */
+      var cancelButtonLabel = (event.data['cancelButtonLabel']);
+      var showSpinner = /** @type {boolean} */ (event.data['showSpinner']);
+      if (typeof(messageId) != 'number' ||
+          typeof(title) != 'string' ||
+          typeof(message) != 'string' ||
+          typeof(infobox) != 'string' ||
+          typeof(buttonLabel) != 'string' ||
+          typeof(showSpinner) != 'boolean') {
+        console.log('Bad show message:', event.data);
+        break;
+      }
+
+      // Set the dialog text.
+      var button = document.getElementById('button-primary');
+      var cancelButton = document.getElementById('button-secondary');
+      var messageDiv = document.getElementById('message');
+      var infoboxDiv = document.getElementById('infobox');
+      document.getElementById('title').innerText = title;
+      document.querySelector('title').innerText = title;
+      messageDiv.innerText = message;
+      if (showSpinner) {
+        messageDiv.classList.add('waiting');
+        messageDiv.classList.add('prominent');
+      }
+      if (infobox != '') {
+        infoboxDiv.innerText = infobox;
+      } else {
+        infoboxDiv.hidden = true;
+      }
+
+      this.initButton_(
+          button,
+          buttonLabel,
+          this.sendReply_.bind(this, event.source, messageId, 1));
+
+      this.initButton_(
+          cancelButton,
+          cancelButtonLabel,
+          this.sendReply_.bind(this, event.source, messageId, 0));
+
+      var buttonToFocus = (cancelButtonLabel) ? cancelButton : button;
+      buttonToFocus.focus();
+
+      // Add a close handler in case the window is closed without clicking one
+      // of the buttons. This will send a 0 as the result.
+      // Note that when a button is pressed, this will result in sendReply_
+      // being called multiple times (once for the button, once for close).
+      chrome.app.window.current().onClosed.addListener(
+          this.sendReply_.bind(this, event.source, messageId, 0));
+
+      this.updateSize_();
+      chrome.app.window.current().show();
+      break;
+
+    case 'update_message':
+      var message = /** @type {string} */ (event.data['message']);
+      if (typeof(message) != 'string') {
+        console.log('Bad update_message message:', event.data);
+        break;
+      }
+
+      var messageDiv = document.getElementById('message');
+      messageDiv.innerText = message;
+
+      this.updateSize_();
+      break;
+
+    default:
+      console.error('Unexpected message:', event.data);
+  }
+};
+
+var messageWindow = new MessageWindowImpl();