deprecate odd variants of SkCanvas::readPixels

Bug: skia:6513
Change-Id: I51179a85f0912d3f899c368c30a943d346dd1d05
Reviewed-on: https://skia-review.googlesource.com/13589
Reviewed-by: Florin Malita <fmalita@chromium.org>
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Reed <reed@google.com>
18 files changed