Revert "Revert "New read pixels implementation that is simpler but does all conversions on CPU.""

This reverts commit be5947c2f38a79b7c709accfb1047d8fd06a0227.

Bug: skia:
Change-Id: I06dc15b31042d7827511d0ac2a7f4262c3f09622
Reviewed-on: https://skia-review.googlesource.com/115079
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
18 files changed