Only handle click actions for left & middle buttons

chrome/browser/resources/md_downloads/crisper.js

Index: chrome/browser/resources/md_downloads/crisper.js
diff --git a/chrome/browser/resources/md_downloads/crisper.js b/chrome/browser/resources/md_downloads/crisper.js
index 55db37276f878b9e72f751573f00b9f95113255b..78bc7981867f3ae6634b4ae33ecaf0d73c46f22a 100644
--- a/chrome/browser/resources/md_downloads/crisper.js
+++ b/chrome/browser/resources/md_downloads/crisper.js
@@ -648,6 +648,8 @@ function queryRequiredElement(selectors, opt_context) {
 
 [ 'click', 'auxclick' ].forEach(function(eventName) {
   document.addEventListener(eventName, function(e) {
+    if (e.button !== 0 && e.button !== 1)
+      return; // Ignore buttons other than left and middle.

[Dan Beam, 2016/09/12 19:18:59]

this is a generated file

you need to update ui/webui/resources/js/util.js and re-run

chrome/browser/resources/vulcanize.py

[Navid Zolghadr, 2016/09/12 19:50:09]

Umm. That is weird. Because I changed this file in the original review and
nobody complained. Was that also incorrect?
https://codereview.chromium.org/2163893003/

I tried modifying utils.js and running vulcanize.py. I got this error running it
from chrome/browser/resources. The error exists event with the tip of the tree
without my changes. Is this error familiar?

TypeError: exceptions must be old-style classes or derived from BaseException,
not NoneType

[Dan Beam, 2016/09/12 21:25:32]

you changed both util.js and crisper.js in similar ways

that part of the exception is not useful, but i'm almost sure you need to
install dependencies

     if (e.defaultPrevented) return;
     var eventPath = e.path;
     var anchor = null;
@@ -6963,4 +6965,4 @@ cr.define('downloads', function() {
 // Copyright 2015 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.
-window.addEventListener('load', downloads.Manager.onLoad);
+window.addEventListener('load', downloads.Manager.onLoad);