Add a chrome://webapks page.

chrome/browser/resources/webapks/about_webapks.js

+// Copyright 2017 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.
+
+/**
+ * Creates and returns a node (with |text| as content) assigning it the
+ * |className| class.

[Dan Beam, 2017/01/25 23:27:33]

@return {HTMLElement}

[gonzalon, 2017/01/26 17:02:49]

Done.

+ */
+function createSpanWithTextAndClass(text, className) {
+  var node = createElementWithClassName('span', className);

[Dan Beam, 2017/01/25 23:27:33]

nit: name this el?  Node and Element are different (Node is a parent class), and
you're calling create*Element*

[gonzalon, 2017/01/26 17:02:49]

Done.

+  node.textContent = text;
+  return node;
+}
+
+/**
+ * Callback from the backend with the information of a WebAPK to display.
+ * This will be called once for each WebAPK available on the device and each
+ * one will be appended at the end of the other.
+ *
+ * @param webApkList List of objects with information about WebAPKs installed.

[Dan Beam, 2017/01/25 23:27:33]

you need a type name in this @param.  an example:

/**
 * @typedef {{
 *   shortName: string,
 *   packageName: string,
 *   shellApkVersion: number,
 *   versionCode: number
 * }}
 */
var WebApkInfo;

@param {!Array<WebApkInfo>} webApkList

[gonzalon, 2017/01/26 17:02:49]

Done.

+ */
+function returnWebApksInfo(webApkList) {
+  for (var i in webApkList) {
+    addWebApk(webApkList[i]);
+  }
+}
+
+/**
+ * Adds a new entry to the page with the information of a WebAPK.
+ *
+ * @param webApkInfo Information about an installed WebAPK.

[Dan Beam, 2017/01/25 23:27:33]

@param {WebApkInfo} webApkInfo

[gonzalon, 2017/01/26 17:02:49]

Done.

+ */
+function addWebApk(webApkInfo) {
+  var webApkList = $('webapk-list');
+
+  webApkList.appendChild(
+      createSpanWithTextAndClass(webApkInfo.shortName, 'app-name'));
+
+  webApkList.appendChild(
+      createSpanWithTextAndClass('Package name: ', 'app-property-label'));
+  webApkList.appendChild(document.createTextNode(webApkInfo.packageName));
+
+  webApkList.appendChild(document.createElement('br'));
+  webApkList.appendChild(createSpanWithTextAndClass(
+      'Shell APK version: ', 'app-property-label'));
+  webApkList.appendChild(document.createTextNode(webApkInfo.shellApkVersion));
+
+  webApkList.appendChild(document.createElement('br'));
+  webApkList.appendChild(
+      createSpanWithTextAndClass('Version code: ', 'app-property-label'));
+  webApkList.appendChild(document.createTextNode(webApkInfo.versionCode));
+}
+
+document.addEventListener('DOMContentLoaded', function() {
+  chrome.send('requestWebApksInfo');
+});