commit e50985b7894dcd0ac65e27d4f917acf6d00502c5
Author: Joel Pittet <joel@pittet.ca>
Date:   Tue Jun 30 16:19:56 2015 -0700

    undo

diff --git a/core/lib/Drupal/Core/Template/Attribute.php b/core/lib/Drupal/Core/Template/Attribute.php
index 8955523..ff01040 100644
--- a/core/lib/Drupal/Core/Template/Attribute.php
+++ b/core/lib/Drupal/Core/Template/Attribute.php
@@ -93,7 +93,7 @@ public function offsetSet($name, $value) {
   protected function createAttributeValue($name, $value) {
     // If the value is already an AttributeValueBase object, return it
     // straight away.
-    if ($value instanceof AttributeValueBase) {
+    if ($value instanceOf AttributeValueBase) {
       return $value;
     }
     // An array value or 'class' attribute name are forced to always be an
@@ -147,7 +147,7 @@ public function addClass() {
       }
 
       // Merge if there are values, just add them otherwise.
-      if (isset($this->storage['class']) && $this->storage['class'] instanceof AttributeArray) {
+      if (isset($this->storage['class']) && $this->storage['class'] instanceOf AttributeArray) {
         // Merge the values passed in from the class value array.
         $classes = array_merge($this->storage['class']->value(), $classes);
         $this->storage['class']->exchangeArray($classes);
@@ -211,7 +211,7 @@ public function removeAttribute() {
    */
   public function removeClass() {
     // With no class attribute, there is no need to remove.
-    if (isset($this->storage['class']) && $this->storage['class'] instanceof AttributeArray) {
+    if (isset($this->storage['class']) && $this->storage['class'] instanceOf AttributeArray) {
       $args = func_get_args();
       $classes = array();
       foreach ($args as $arg) {
@@ -239,7 +239,7 @@ public function removeClass() {
    *   Returns TRUE if the class exists, or FALSE otherwise.
    */
   public function hasClass($class) {
-    if (isset($this->storage['class']) && $this->storage['class'] instanceof AttributeArray) {
+    if (isset($this->storage['class']) && $this->storage['class'] instanceOf AttributeArray) {
       return in_array($class, $this->storage['class']->value());
     }
     else {