Add Physical Web WebUI Default Url Icon

components/physical_web/webui/resources/physical_web.js

 // Copyright (c) 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.
 
 /**
  * Takes the |nearbyUrlsData| input argument which holds metadata for web pages
  * broadcast by nearby devices.
  * @param {Object} nearbyUrlsData Information about web pages broadcast by
  *      nearby devices
  */
 function renderTemplate(nearbyUrlsData) {
   if (nearbyUrlsData['metadata'].length != 0) {
     $('empty-list-container').hidden = true;
   }
   // This is a workaround with jstemplate. Jstemplate render only works on empty
   // node. When we need to rerender things, we have to remove previous nodes.
   let renderContainer = document.getElementById('render-container');
   // Remove existing childNode.
   while (renderContainer.hasChildNodes()) {
     renderContainer.removeChild(renderContainer.lastChild);
   }
   let templateDiv = document.getElementById('render-template').cloneNode(true);
   renderContainer.appendChild(templateDiv);
 
   // This is the javascript code that processes the template:
   jstProcess(new JsEvalContext(nearbyUrlsData), templateDiv);
 
+  assignImageLoadErrorHandlers();
+
   let bodyContainer = $('body-container');
   bodyContainer.hidden = false;
 }
 
 function physicalWebPageLoaded() {
   chrome.send('physicalWebPageLoaded');
 }
 
 function physicalWebItemClicked(index) {
   chrome.send('physicalWebItemClicked', [index]);
 }
 
 function pushNearbyURLs(nearbyUrlsData) {
   renderTemplate(nearbyUrlsData);
 }
 
+function assignImageLoadErrorHandlers() {
+  var pwIcons = document.querySelectorAll('.physicalWebIcon');
+  pwIcons.forEach(function(e) {
+    let img = e.getElementsByTagName('img')[0];
+    img.addEventListener('error', function() {
+      img.src =
+          'chrome://physical-web/ic_link_grey600_36dp.png';
+    });
+  });
+}
+
 document.addEventListener('DOMContentLoaded', physicalWebPageLoaded);