Revert of Move BUILD.public to public.bzl. (patchset #1 id:1 of https://codereview.chromium.org/1577353002/ )

Reason for revert:
Corresponding google-private changes not ready.

Original issue's description:
> Move BUILD.public to public.bzl.
>
> This allows building with bazel (see http://bazel.io).
>
> BUG=skia:
> GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1577353002
>
> Committed: https://skia.googlesource.com/skia/+/eeebfff54877b24151570c4f02b2299e3f9ef967

TBR=benjaminwagner@google.com,mtklein@google.com
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=skia:

Review URL: https://codereview.chromium.org/1580923002
1 file changed