Move resource ref/io manipulation from GrProgramElement to GrProcessor

Change-Id: I783e74107f7d34b57d80b843fe23ce7126b77424
Reviewed-on: https://skia-review.googlesource.com/6816
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
6 files changed