Revert "Revert "Remove copyTo() legacy API flag from bzl""

Revert "Revert "Remove copyTo() legacy API flag from bzl""

This reverts commit d271ba268876d3feca13e02d0a92ecaf79b6ddfc.

Reason for revert: Client failures should be fixed.  Will keep an eye on the roller.

Original change's description:
> Revert "Remove copyTo() legacy API flag from bzl"
>
> This reverts commit 65083e444c03cedecf45bc38bb8fea27e91e0a9e.
>
> Reason for revert: Causes build failures.
>
> Original change's description:
> > Remove copyTo() legacy API flag from bzl
> >
> > NOTRY=true
> >
> > Bug: skia:6464
> > Change-Id: Ia3935998960054df9e54cfb2aead66549c629c04
> > Reviewed-on: https://skia-review.googlesource.com/15001
> > Reviewed-by: Matt Sarett <msarett@google.com>
> > Commit-Queue: Matt Sarett <msarett@google.com>
> >
>
> TBR=msarett@google.com
> NOPRESUBMIT=true
> NOTREECHECKS=true
> NOTRY=true
>
> Change-Id: I9d82c7b699e106238981e32553e975c91e42cfb8
> Reviewed-on: https://skia-review.googlesource.com/15021
> Reviewed-by: Ben Wagner <benjaminwagner@google.com>
> Commit-Queue: Ben Wagner <benjaminwagner@google.com>
>

TBR=benjaminwagner@google.com,msarett@google.com,reviews@skia.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Change-Id: Ie9c9c1f8d06c8b422b8902e39645cd0d887d6b49
Reviewed-on: https://skia-review.googlesource.com/15150
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>