Make a ctor for SkGlyph

Change-Id: I21a5ed81d3e161ddf8a838ea9ac0414265b00ae6
Reviewed-on: https://skia-review.googlesource.com/c/182701
Auto-Submit: Herb Derby <herb@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Herb Derby <herb@google.com>
6 files changed