Make fPathData private and add API for paths

The new API eliminates all need to access the path inner workings.

There are some uses of the cast (SkGlyph*) these are to facilitate
the larger change this is a part of. The will be eliminated when all
is done.

Some of the code has been changed to use strike->glyph(id) and SkGlyph*
to help with the flow of the code.

Change-Id: Id8dc84076f56e1e39450367a0440d15954dbdc71
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/220523
Commit-Queue: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
15 files changed