Make GrShape lazily initialize an original path for gen id change listeners

Change-Id: I3a1cb400190cf18241436b7e655a4a267bb2e22d
Reviewed-on: https://skia-review.googlesource.com/90482
Commit-Queue: Brian Salomon <bsalomon@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
3 files changed