https://bugs.webkit.org/show_bug.cgi?id=96331
[UxD] Vertical lists should always be scrollable
PR #195305

Reviewed by Yong Li.
Patch by Antonio Gomes <agomes@rim.com>
Internally reviewed by Gen Mak.

Check if the RenderLayer is composited / hardware acceleratable prior to
check if its contents overflows. If that is the case, check if
our custom data-blackberry-force-overscroll is present.

That makes it possible for us to align to UX requirements: settings
and CCM panels should be always scrollable.

* Api/InRegionScroller.cpp:
(BlackBerry::WebKit::canScrollRenderBox):
* WebKitSupport/InRegionScrollableArea.cpp:
(BlackBerry::WebKit::InRegionScrollableArea::InRegionScrollableArea):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@128142 268f45cc-cd09-0410-ab3c-d52691b4dbfc