trim off more bgra stages

Same deal as before, just swap_rb where needed.

The change to SkWebpCodec could probably land independently if we want.

Change-Id: Idd53ab76232cb95eb2f41cd65c6903fa7c5b01d6
Reviewed-on: https://skia-review.googlesource.com/c/163440
Commit-Queue: Brian Osman <brianosman@google.com>
Auto-Submit: Mike Klein <mtklein@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
8 files changed