Enhance GTK DRT implementation to support platform scroll wheel events.

DRT layout tests gained the ability to simulate mouse scroll wheel events in http://trac.webkit.org/changeset/55739.  Currently this is only supported on Mac OS 10.5 and 10.6.  The GTK DRT implementation should be enhanced to dispatch scroll wheel events, and layout tests that utilize this functionality should be removed from the Skipped file.

Created an attachment (id=146016) [details]
Patch

CC-ing reviewers to have a look at the patch.

(From update of attachment 146016 [details])
View in context: https://bugs.webkit.org/attachment.cgi?id=146016&action=review

Looks good, just a few style nits. Can't we unskip some tests now?

> Tools/DumpRenderTree/gtk/EventSender.cpp:483
> +    int horizontal = (int)JSValueToNumber(context, arguments[0], exception);
> +    g_return_val_if_fail((!exception || !*exception), JSValueMakeUndefined(context));
> +    int vertical = (int)JSValueToNumber(context, arguments[1], exception);
> +    g_return_val_if_fail((!exception || !*exception), JSValueMakeUndefined(context));

You should use static_cast here instead of C-style casts. Is it possible to just elminate the cast entirely here?

> Tools/DumpRenderTree/gtk/EventSender.cpp:487
> +    gboolean paged = false;
> +    if (argumentCount == 3) {
> +        paged = JSValueToBoolean(context, arguments[2]);

bool intead of gboolean would be more appropriate here. Why does paged need to be defined in outer scope? Seems like this could just be:

g_return_val_if_fail(argumentcount < 3 || !JSValueToBoolean(context, arguments[2]), JSValueMakeUndefined(context));

Fix for #88070 already includes the implementation of DumpRenderTree smooth scroll wheel events for Gtk.