Don't perform analysis twice in InstancedRendering::Op

Change-Id: Ie0aeeb7bf63090b0c27a9b062cce0cdc561a1d7e
Reviewed-on: https://skia-review.googlesource.com/10583
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
3 files changed