Revert of Add alternate SkPicture::clone (https://codereview.chromium.org/381193002/)

Reason for revert:
Going to try to just remove the many-at-once clone interface

Original issue's description:
> Add alternate SkPicture::clone
>
> This adds an alternate version of SkPicture::clone for two reasons:
>
> 1) Chromium uses the SkPicture copy constructor to unpack the pictures from the old-style clone interface (and I would like to remove the copy ctor)
>
> 2) This is part of the long term plan to wean Chrome off of cloning. Once pictures are thread safe we will switch the new SkPicture::clone call to just return 'this'. From there it is a small step to removing clone entirely.
>
> Note that the two versions of clone() is temporary. Once this is landed (and rolled) I will land a Chrome-side patch to remove their use of the old interface (Use new SkPicture::clone interface - https://codereview.chromium.org/380323002/)
>
> Committed: https://skia.googlesource.com/skia/+/e372e78223a8ce916d276d6e0420d552fb0267e9

R=mtklein@google.com, reed@google.com
TBR=mtklein@google.com, reed@google.com
NOTREECHECKS=true
NOTRY=true

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/386933004
2 files changed