Change SkTArray::size to return int

Change-Id: I1e1e316eeabc3d05b03302a0de57bf28d8e393b4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/600339
Reviewed-by: John Stiles <johnstiles@google.com>
Commit-Queue: Herb Derby <herb@google.com>
27 files changed