Add an extra check for an e.target.className.indexOf function (bvaughn#1210)

* check if an e.target has a className with an indexOf function

* Delete detectElementResize_20180906173208.js

sorry, forgot to add vscode .history to .gitignore

* Delete detectElementResize_20180906173856.js

sorry, forgot to add vscode .history to .gitignore

Author: dmydry

source/vendor/detectElementResize.js

@@ -71,6 +71,8 @@ export default function createDetectElementResize(nonce) {
     var scrollListener = function(e) {
       // Don't measure (which forces) reflow for scrolls that happen inside of children!
       if (
+        e.target.className &&
+        typeof e.target.className.indexOf === 'function' &&
         e.target.className.indexOf('contract-trigger') < 0 &&
         e.target.className.indexOf('expand-trigger') < 0
       ) {