merge from dev

dashboard-ui/bower_components/webcomponentsjs/MutationObserver.js

@@ -7,7 +7,7 @@
  * Code distributed by Google as part of the polymer project is also
  * subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
  */
-// @version 0.7.14
+// @version 0.7.19
 if (typeof WeakMap === "undefined") {
   (function() {
     var defineProperty = Object.defineProperty;
@@ -45,6 +45,9 @@ if (typeof WeakMap === "undefined") {
 }
 
 (function(global) {
+  if (global.JsMutationObserver) {
+    return;
+  }
   var registrationsTable = new WeakMap();
   var setImmediate;
   if (/Trident|Edge/.test(navigator.userAgent)) {
@@ -340,5 +343,8 @@ if (typeof WeakMap === "undefined") {
     }
   };
   global.JsMutationObserver = JsMutationObserver;
-  if (!global.MutationObserver) global.MutationObserver = JsMutationObserver;
+  if (!global.MutationObserver) {
+    global.MutationObserver = JsMutationObserver;
+    JsMutationObserver._isPolyfilled = true;
+  }
 })(self);