Add Thin LTO to OptimizeForSize builds

Bug: skia:13657
Change-Id: I289685ce71875fdc4d73f5e41107d87f5b5cdeb2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/583248
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
2 files changed