We need this since we have texture generators that draw the base level
but nothing more. Thus we want them to be able to directly draw into
a pre allocated mipped target instead of doing a copy later.
TBR: bsalomon@google.com
Bug: skia:
Change-Id: I1dfae0da7153b21b30fdfa51a7061fc255739a1e
Reviewed-on: https://skia-review.googlesource.com/54100
Reviewed-by: Brian Salomon <bsalomon@google.com>
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
e1da1d9a7d