DOMException toString is not correct

LayoutTests/fast/forms/input-stepup-stepdown.html

Index: LayoutTests/fast/forms/input-stepup-stepdown.html
diff --git a/LayoutTests/fast/forms/input-stepup-stepdown.html b/LayoutTests/fast/forms/input-stepup-stepdown.html
index b261f4e4c0f15180e2f4a0b68587823187fc170f..2a9ed272427dfa0de8a21c7841aa753e5c5fde50 100644
--- a/LayoutTests/fast/forms/input-stepup-stepdown.html
+++ b/LayoutTests/fast/forms/input-stepup-stepdown.html
@@ -10,14 +10,14 @@
 description('Check stepUp() and stepDown() bahevior for unsupported types.');
 
 var input = document.createElement('input');
-var invalidStateErr = '"Error: InvalidStateError: DOM Exception 11"';
+var invalidStateErr = '"InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable."';
 
 debug('Unsupported type');
 input.type = 'text';
-shouldThrow('input.step = "3"; input.min = ""; input.max = ""; input.value = "2"; input.stepDown()', '"Error: InvalidStateError: DOM Exception 11"');
-shouldThrow('input.stepDown(0)', '"Error: InvalidStateError: DOM Exception 11"');
-shouldThrow('input.stepUp()', '"Error: InvalidStateError: DOM Exception 11"');
-shouldThrow('input.stepUp(0)', '"Error: InvalidStateError: DOM Exception 11"');
+shouldThrow('input.step = "3"; input.min = ""; input.max = ""; input.value = "2"; input.stepDown()', '"InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable."');
+shouldThrow('input.stepDown(0)', '"InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable."');
+shouldThrow('input.stepUp()', '"InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable."');
+shouldThrow('input.stepUp(0)', '"InvalidStateError: An attempt was made to use an object that is not, or is no longer, usable."');
 </script>
 <script src="../../fast/js/resources/js-test-post.js"></script>
 </body>