Create indirect index buffer for tessellation during onPrepare

Change-Id: I78d74976fa2252da2a40862c241a99b68d27fb40
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/292259
Reviewed-by: Greg Daniel <egdaniel@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
3 files changed