Reviewed by Eric Seidel.

        Changed the toString behaviour for non document dom node event handlers in the V8 bindings.
        https://bugs.webkit.org/show_bug.cgi?id=25544

        In the V8 bindings non document dom node event handlers are wrapped in a number of with blocks and uses an inner
        function. This causes the default toString on such a handler to return all this wrapper code. As some web sites
        use the source of an event handler to create new functions this wrapper code causes compatibility problems.

        Create a specific toString function for these handlers which will return a function source compatible with the
        source returned by the JSC bindings and other browsers.

        Test: fast/events/event-function-toString.html

        * bindings/v8/ScriptEventListener.cpp:
        (WebCore::createAttributeEventListener):
        * bindings/v8/V8LazyEventListener.cpp:
        (WebCore::V8LazyEventListener::V8LazyEventListener):
        (WebCore::V8LazyEventListener::getListenerFunction):
        (WebCore::V8LazyEventListenerToString):
        (WebCore::V8LazyEventListener::getWrappedListenerFunction):
        * bindings/v8/V8LazyEventListener.h:
        (WebCore::V8LazyEventListener::create):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@43289 268f45cc-cd09-0410-ab3c-d52691b4dbfc