Use SkStrikeSpec to consolidate SkDescriptor, Effects and Typeface.

Introduce SkStrikeSpec. Allow an SkStrikeInterface to return on
that represents the strike. Have GrTextBlob::Run::setFont() use
SkStrikeSpecs.

Misc Cleanups
* In SkStrikeCache::Node - rename fCache -> fStrike
* Parameter reformatting

Change-Id: I1b289e2cb4e5252d5c3cb776f3b2a31c6e1948b3
Reviewed-on: https://skia-review.googlesource.com/c/192029
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
8 files changed