fix(tabs): ie10 MutationObserver issue (#9397)

Author: j3ski

src/components/tabs/js/tabsDummyWrapperDirective.js

@@ -6,38 +6,49 @@ angular
  * @private
  *
  * @param $mdUtil
+ * @param $window
  * @returns {{require: string, link: link}}
  * @constructor
- * 
+ *
  * @ngInject
  */
-function MdTabsDummyWrapper ($mdUtil) {
+function MdTabsDummyWrapper ($mdUtil, $window) {
   return {
     require: '^?mdTabs',
     link:    function link (scope, element, attr, ctrl) {
       if (!ctrl) return;
 
-      var observer = new MutationObserver(function(mutations) {
+      var observer;
+      var disconnect;
+
+      var mutationCallback = function() {
         ctrl.updatePagination();
         ctrl.updateInkBarStyles();
-      });
-
-      var config = {
-        childList: true,
-        subtree: true,
-        // Per https://bugzilla.mozilla.org/show_bug.cgi?id=1138368, browsers will not fire
-        // the childList mutation, once a <span> element's innerText changes.
-        // The characterData of the <span> element will change.
-        characterData: true
       };
 
-      observer.observe(element[0], config);
+      if('MutationObserver' in $window) {
+        var config = {
+          childList: true,
+          subtree: true,
+          // Per https://bugzilla.mozilla.org/show_bug.cgi?id=1138368, browsers will not fire
+          // the childList mutation, once a <span> element's innerText changes.
+          // The characterData of the <span> element will change.
+          characterData: true
+        };
+
+        observer = new MutationObserver(mutationCallback);
+        observer.observe(element[0], config);
+        disconnect = observer.disconnect.bind(observer);
+      } else {
+        var debounced = $mdUtil.debounce(mutationCallback, 15, null, false);
+        
+        element.on('DOMSubtreeModified', debounced);
+        disconnect = element.off.bind(element, 'DOMSubtreeModified', debounced);
+      }
 
       // Disconnect the observer
       scope.$on('$destroy', function() {
-        if (observer) {
-          observer.disconnect();
-        }
+        disconnect();
       });
     }
   };