Make length property return useful values for DOM bindings functions

Source/bindings/v8/V8DOMConfiguration.cpp

Index: Source/bindings/v8/V8DOMConfiguration.cpp
diff --git a/Source/bindings/v8/V8DOMConfiguration.cpp b/Source/bindings/v8/V8DOMConfiguration.cpp
index 654f825df58336e595f418eebcee6e4954554a10..93bfa15cc1c2f8826fdd0ae84eaabc862a27ab9d 100644
--- a/Source/bindings/v8/V8DOMConfiguration.cpp
+++ b/Source/bindings/v8/V8DOMConfiguration.cpp
@@ -54,7 +54,7 @@ void V8DOMConfiguration::batchConfigureCallbacks(v8::Handle<v8::ObjectTemplate>
         v8::InvocationCallback callback = callbacks[i].callback;
         if (currentWorldType == MainWorld && callbacks[i].callbackForMainWorld)
             callback = callbacks[i].callbackForMainWorld;
-        prototype->Set(v8::String::NewSymbol(callbacks[i].name), v8::FunctionTemplate::New(callback, v8Undefined(), signature), attributes);
+        prototype->Set(v8::String::NewSymbol(callbacks[i].name), v8::FunctionTemplate::New(callback, v8Undefined(), signature, callbacks[i].length), attributes);
     }
 }