Comment 10 for bug 1553428

Attached is a patch that due to the broken nature of scroll bars in osx on both cairo and opengl it just disables/hides the scrollbars and stops them being updated.

On OpenGL the scrollbars are never visible
On Cairo the scollbars do not display the full width/height of the canvas and are only visible around the scroll handle

This has no effect on legacy canvas where the scrollbars do work correctly