Only store width and height on SkPixelRef

Bug: skia:6535
Change-Id: Id91e8d1e82f593be7d4b23ca5abde752f2666a77
Reviewed-on: https://skia-review.googlesource.com/14105
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Mike Reed <reed@google.com>
11 files changed