Revert "Respect canvas size and frame offset in webp decoder"

This reverts commit 0f33970c8d950a68b7d83cc626ac0500953d6b15.

Reason for revert: msan complaint

Original change's description:
> Respect canvas size and frame offset in webp decoder
> 
> BUG=skia:6185
> 
> Change-Id: Id543cb689a5e33b800ebbc18f4a234e78a4c4298
> Reviewed-on: https://skia-review.googlesource.com/7800
> Commit-Queue: Matt Sarett <msarett@google.com>
> Reviewed-by: Leon Scroggins <scroggo@google.com>
> 

TBR=borenet@google.com,msarett@google.com,scroggo@google.com,reviews@skia.org
# Not skipping CQ checks because original CL landed > 1 day ago.
BUG=skia:6185

Change-Id: Ie01dc7d7ebfebe36a235335d0d8cb28bccb2ecff
Reviewed-on: https://skia-review.googlesource.com/8046
Commit-Queue: Robert Phillips <robertphillips@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
5 files changed