Implement SkHeifCodec::onRewind

Bug: 130458015
Test: Id2d70e95d2d879d2ff5e2cb985d3542731108909

SkHeifCodec needs to reset some of its state between decoding calls. Do
so in onRewind. This mimics SkJpegCodec, on which SkHeifCodec is
modelled.

Change-Id: I380a8ed88c98eaedc6f6ff1ff115bb2dea68bd56
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/208180
Auto-Submit: Leon Scroggins <scroggo@google.com>
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
2 files changed