Do not auto-generate instanceOf methods.

lib/dom/templates/dom/native/cpp_header.template

Index: lib/dom/templates/dom/native/cpp_header.template
diff --git a/lib/dom/templates/dom/native/cpp_header.template b/lib/dom/templates/dom/native/cpp_header.template
index ea89fd7bf04f87a40d213ec73fe4a88c086f32a0..315588a25f72b79d3d04a443cb9d4861034d2dcc 100644
--- a/lib/dom/templates/dom/native/cpp_header.template
+++ b/lib/dom/templates/dom/native/cpp_header.template
@@ -23,11 +23,6 @@ struct Dart$INTERFACE {
         return DartDOMWrapper::unwrapDartWrapper<Dart$INTERFACE>(handle, exception);
     }
 
-    static bool instanceOf(Dart_Handle handle)
-    {
-        return DartDOMWrapper::instanceOf(dartImplementationClassName, handle);
-    }
-
     static Dart_NativeFunction resolver(Dart_Handle name, int argumentCount);
 };