[Md Feedback] Add initial data population for dialog.

chrome/browser/resources/md_feedback/feedback.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.
+
+cr.define('feedback', function() {
+  'use strict';
+
+  /**
+   * The feedback-container element. Initialized after Polymer is ready.
+   * @type {?FeedbackContainer}
+   */
+  var container = null;
+
+  /**
+   * Initialize the Feedback WebUI by requesting data to populate the current
+   * feedback form.
+   */
+  function initialize() {
+    container = /** @type {!FeedbackContainerElement} */
+        ($('container'));
+
+    feedback.browserApi.requestData();
+  }
+
+  return {
+    initialize: initialize,
+  };
+});
+
+// API invoked by the browser MdFeedbackWebUIMessageHandler to communicate
+// with this UI.
+cr.define('feedback.ui', function() {
+  'use strict';
+
+  /**
+   * Populates the feedback form with data.
+   *
+   * @param {{email: string|undefined,
+   *          url: string|undefined}} data
+   * Parameters in data:
+   *   email - user's email, if available.
+   *   url - url of the tab the user was on before triggering feedback.
+   */
+  function setData(data) {
+    container.email = data['email'];
+    container.url = data['url'];
+  }
+
+  return {
+    setData: setData,
+  };
+});
+
+// API invoked by this UI to communicate with the browser WebUI message
+// handler.
+cr.define('feedback.browserApi', function() {
+  'use strict';
+
+  /**
+   * Requests data to initialize the WebUI with.
+   * The data will be returned via feedback.ui.setData.
+   */
+  function requestData() {
+    chrome.send('requestData');
+  }
+
+  return {
+    requestData: requestData,
+  };
+});
+
+window.addEventListener('load', feedback.initialize);