use std::make_unique

Change-Id: I7c672ff6b8eb95ec8c1123a5bfdb202e1644f494
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259281
Commit-Queue: Mike Klein <mtklein@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
103 files changed