SkGlyphRect is a rectangle encoding specialized for
union and intersect. It will be used for calculating
the bounding boxes of glyph runs, and clipping glyphs
for GPU.
Change-Id: Icab826b51dc2254ee4006ada84f7fc09e112a933
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/319697
Reviewed-by: Ben Wagner <bungeman@google.com>
Commit-Queue: Herb Derby <herb@google.com>
