From 5ea03792e8439c5b9dac8f151afb6bf585ee6180 Mon Sep 17 00:00:00 2001
From: Piotr Gejgalis <piotr@gejgalis.com>
Date: Mon, 11 May 2015 13:00:33 +0200
Subject: [PATCH] Updated polyfill to fix IE10 issue
 https://github.com/webcomponents/webcomponentsjs/commit/feef1883d19c80072c411b332cf97e3e99c11941

---
 index.js | 34 ++++++++++++++++++++++++++--------
 1 file changed, 26 insertions(+), 8 deletions(-)

diff --git a/index.js b/index.js
index bbc7ced..c0a6b0f 100644
--- a/index.js
+++ b/index.js
@@ -49,11 +49,30 @@ if (typeof WeakMap === 'undefined') {
 
 var registrationsTable = new WeakMap();
 
-// We use setImmediate or postMessage for our future callback.
-var setImmediate = window.msSetImmediate;
-
-// Use post message to emulate setImmediate.
-if (!setImmediate) {
+var setImmediate;
+
+// As much as we would like to use the native implementation, IE
+// (all versions) suffers a rather annoying bug where it will drop or defer
+// callbacks when heavy DOM operations are being performed concurrently.
+//
+// For a thorough discussion on this, see:
+// http://codeforhire.com/2013/09/21/setimmediate-and-messagechannel-broken-on-internet-explorer-10/
+if (/Trident|Edge/.test(navigator.userAgent)) {
+  // Sadly, this bug also affects postMessage and MessageQueues.
+  //
+  // We would like to use the onreadystatechange hack for IE <= 10, but it is
+  // dangerous in the polyfilled environment due to requiring that the
+  // observed script element be in the document.
+  setImmediate = setTimeout;
+
+// If some other browser ever implements it, let's prefer their native
+// implementation:
+} else if (window.setImmediate) {
+  setImmediate = window.setImmediate;
+
+// Otherwise, we fall back to postMessage as a means of emulating the next
+// task semantics of setImmediate.
+} else {
   var setImmediateQueue = [];
   var sentinel = String(Math.random());
   window.addEventListener('message', function(e) {
@@ -542,7 +561,6 @@ Registration.prototype = {
         // Fall through.
       case 'DOMNodeInserted':
         // http://dom.spec.whatwg.org/#concept-mo-queue-childlist
-        var target = e.relatedNode;
         var changedNode = e.target;
         var addedNodes, removedNodes;
         if (e.type === 'DOMNodeInserted') {
@@ -557,13 +575,13 @@ Registration.prototype = {
         var nextSibling = changedNode.nextSibling;
 
         // 1.
-        var record = getRecord('childList', target);
+        var record = getRecord('childList', e.target.parentNode);
         record.addedNodes = addedNodes;
         record.removedNodes = removedNodes;
         record.previousSibling = previousSibling;
         record.nextSibling = nextSibling;
 
-        forEachAncestorAndObserverEnqueueRecord(target, function(options) {
+        forEachAncestorAndObserverEnqueueRecord(e.relatedNode, function(options) {
           // 2.1, 3.2
           if (!options.childList)
             return;