Fix remaining issue with bug #5904777

LEFT alignment in an RTL environment had the wrong 'gravity'.

This was due to a modelling error in GridLayout which is fixed in this CL.

Also apply some very minor simplifications and refactorings following the
addition of RTL support.

Change-Id: I153bc06d3c22dcb9954e4cbdfa89625823239b89
1 file changed