Add filter to SkTHashTable and SkTHashMap

Filter takes a bool function where fales means remove the entry.

Change-Id: I768baed6a4e26308f571b0b595ae19aea9d8dca7
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/259821
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
2 files changed