Start sending auxclick instead of click for non-primary buttons

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.
@@ skipping 194 matching lines @@
  * @return {!HTMLElement} the Element.
  */
 function queryRequiredElement(selectors, opt_context) {
   var element = (opt_context || document).querySelector(selectors);
   return assertInstanceof(element, HTMLElement,
                           'Missing required element: ' + selectors);
 }
 
 // Handle click on a link. If the link points to a chrome: or file: url, then
 // call into the browser to do the navigation.
-document.addEventListener('click', function(e) {
-  if (e.defaultPrevented)
-    return;
+['click', 'auxclick'].forEach(function(eventName) {
+  document.addEventListener(eventName, function(e) {
+    if (e.defaultPrevented)
+      return;
 
-  var el = e.target;
-  if (el.nodeType == Node.ELEMENT_NODE &&
-      el.webkitMatchesSelector('A, A *')) {
-    while (el.tagName != 'A') {
-      el = el.parentElement;
+    var el = e.target;
+    if (el.nodeType == Node.ELEMENT_NODE &&
+        el.webkitMatchesSelector('A, A *')) {
+      while (el.tagName != 'A') {
+        el = el.parentElement;
+      }
+
+      if ((el.protocol == 'file:' || el.protocol == 'about:') &&
+          (e.button == 0 || e.button == 1)) {
+        chrome.send('navigateToUrl', [
+          el.href,
+          el.target,
+          e.button,
+          e.altKey,
+          e.ctrlKey,
+          e.metaKey,
+          e.shiftKey
+        ]);
+        e.preventDefault();
+      }
     }
-
-    if ((el.protocol == 'file:' || el.protocol == 'about:') &&
-        (e.button == 0 || e.button == 1)) {
-      chrome.send('navigateToUrl', [
-        el.href,
-        el.target,
-        e.button,
-        e.altKey,
-        e.ctrlKey,
-        e.metaKey,
-        e.shiftKey
-      ]);
-      e.preventDefault();
-    }
-  }
+  });
 });
 
 /**
  * Creates a new URL which is the old URL with a GET param of key=value.
  * @param {string} url The base URL. There is not sanity checking on the URL so
  *     it must be passed in a proper format.
  * @param {string} key The key of the param.
  * @param {string} value The value of the param.
  * @return {string} The new URL.
  */
@@ skipping 182 matching lines @@
         case 0xdb: return '[';
         case 0xdd: return ']';
       }
       return 'Unidentified';
     }
   });
 } else {
   window.console.log("KeyboardEvent.Key polyfill not required");
 }
 // </if>  /* is_ios */