Fix matrix multiply in accessiblity display adjustments.

Fixed a bug caused by a missing temporary when swapping two
matrices.  This could produce undefined results in the case where
both display inversion and the greyscale daltonizer were enabled
simultaneously.

Tightened up the code a little to make this kind of error
less likely by removing redundant state.

Removed the native prefix on some methods since they are not
native at all.

Change-Id: I716ffc8fbe76a304c60d45870074340c0121059f