plumb through arenaalloc
- simplifies the older pattern of storage/size
- removes a dynamic allocation in defaultbitmapcontroller

Bug: skia:
Change-Id: Ibc937d3e0c057e78cc0c8bf7d9ad2d824eb240d9
Reviewed-on: https://skia-review.googlesource.com/141321
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Mike Reed <reed@google.com>
5 files changed