Move Op chain bounds calculations into tryConcat

Bug: skia:8671
Change-Id: I253a753db1aa225bd4e0a7e9bd869dbd52f2f063
Reviewed-on: https://skia-review.googlesource.com/c/185811
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Chris Dalton <csmartdalton@google.com>
2 files changed