Add GrOp::wasRecorded and use in instanced rendering for tracking.

BUG=skia:

Change-Id: I4c5cdf47d42b7adae3649c7f96caabe68f45acbf
Reviewed-on: https://skia-review.googlesource.com/9308
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Chris Dalton <csmartdalton@google.com>
4 files changed