WebUI: Fix/suppress some existing violations of no-restricted-globals.

ui/webui/resources/js/util.js

 // Copyright (c) 2012 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.
 
 // <include src="assert.js">
 
 /**
  * Alias for document.getElementById. Found elements must be HTMLElements.
  * @param {string} id The ID of the element to find.
  * @return {HTMLElement} The found element or null if not found.
  */
 function $(id) {
+  // Disable getElementById restriction here, since we are instructing other
+  // places to re-use the $() that is defined here.
+  // eslint-disable-next-line no-restricted-properties
   var el = document.getElementById(id);
   return el ? assertInstanceof(el, HTMLElement) : null;
 }
 
 // TODO(devlin): This should return SVGElement, but closure compiler is missing
 // those externs.
 /**
  * Alias for document.getElementById. Found elements must be SVGElements.
  * @param {string} id The ID of the element to find.
  * @return {Element} The found element or null if not found.
  */
 function getSVGElement(id) {
-  var el = document.getElementById(id);
+  var el = $(id);

[dpapad, 2017/06/06 19:25:51]

Well, that was the culprit for the failing tests. Justified, since getSVGElement
can't delegate to $(), because the latter asserts for HTMLELement, which SVG
elements do not inherit from.

   return el ? assertInstanceof(el, Element) : null;
 }
 
 /**
  * Add an accessible message to the page that will be announced to
  * users who have spoken feedback on, but will be invisible to all
  * other users. It's removed right away so it doesn't clutter the DOM.
  * @param {string} msg The text to be pronounced.
  */
 function announceAccessibleMessage(msg) {
@@ skipping 495 matching lines @@
   });
 }
 
 /**
  * @param {!Event} e
  * @return {boolean} Whether a modifier key was down when processing |e|.
  */
 function hasKeyModifiers(e) {
   return !!(e.altKey || e.ctrlKey || e.metaKey || e.shiftKey);
 }