Have SkStrikeCache track memory usage

Have the SkStrikeCache track all memory usage. This
moves all the validation code to the SkStrikeCache and
out of the SkScalerCache.

* Some header cleanup.

Change-Id: I9c0a3bb217299deed12223221e2bb5fd09eadb39
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/271740
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
4 files changed