Revert "remove (empty) SkXfermode.h"

This reverts commit c5619cd1702759990f278ed87c3654a292f044d1.

Reason for revert: Want to keep Google3 green & be able to detect other changes breaking it.

Change-Id: I3a651d0996838ed12bc0cfc6ed464a2cee37fba4
Reviewed-on: https://skia-review.googlesource.com/5381
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed