Properly align inside GrTextBlob.

In particular, on 32 bit machines GrTextBlob::Run may have higher
alignment requirements than the types which are stored before it in the
slab allocation. This sometimes manifests in unaligned access errors
when drawing an odd number of glyphs.

Change-Id: I6445001b3b3f1401eb53d988efd4cba835a100db
Reviewed-on: https://skia-review.googlesource.com/155980
Reviewed-by: Kevin Lubick <kjlubick@google.com>
Commit-Queue: Ben Wagner <bungeman@google.com>
1 file changed