Add method to html_dartium utils to check for NSM errors

sdk/lib/html/dartium/html_dartium.dart

Index: sdk/lib/html/dartium/html_dartium.dart
diff --git a/sdk/lib/html/dartium/html_dartium.dart b/sdk/lib/html/dartium/html_dartium.dart
index 555a0d096add4228a1103dd1d6107c04a630c765..ec64c9348bf78f41aaa4b71f828451c1fd552676 100644
--- a/sdk/lib/html/dartium/html_dartium.dart
+++ b/sdk/lib/html/dartium/html_dartium.dart
@@ -32031,6 +32031,8 @@ class _Utils {
   // TODO(jacobr): we need a failsafe way to determine that a Node is really a
   // DOM node rather than just a class that extends Node.
   static bool isNode(obj) => obj is Node;
+
+  static bool isNoSuchMethodError(obj) => obj is NoSuchMethodError;
 }
 
 class _NPObject extends NativeFieldWrapperClass1 {