DDLTileHelper: Use SkAutoTArray instead of raw pointer

Noticed this while poking around.

Change-Id: Ibc371cc3dcf2ed4b1e029ec74b16bb41a4b8e592
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/289017
Auto-Submit: Adlai Holler <adlai@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
2 files changed