minimize includes and forwards for remote glyph cache

Change-Id: I83472d8eeb248be20db68d8f05cab9b98b8d77cc
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/320558
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
3 files changed