Update stencil ops to have a parallel proxyID

Change-Id: I842c7f2011c8b9d4487cec4349de8b77f326a381
Reviewed-on: https://skia-review.googlesource.com/11360
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Brian Salomon <bsalomon@google.com>
7 files changed