fix(autocomplete): waits for screen to reposition on focus before

locking scrolling

Closes #2973

Author: Robert Messerle

src/components/autocomplete/js/autocompleteController.js

@@ -200,7 +200,7 @@ function MdAutocompleteCtrl ($scope, $element, $mdUtil, $mdConstant, $timeout, $
   function handleHiddenChange (hidden, oldHidden) {
     if (!hidden && oldHidden) positionDropdown();
     if (!hidden) {
-      if (elements) $mdUtil.disableScrollAround(elements.ul);
+      if (elements) $timeout(function () { $mdUtil.disableScrollAround(elements.ul); }, 0, false);
     } else {
       $mdUtil.enableScrolling();
     }