SkMetaData: drop unused pointer ownership

Change-Id: Iff3b14868480b8c5f0029df8516cfaea0d05ac8a
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/230892
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Hal Canary <halcanary@google.com>
2 files changed