Remove support for SkPicture::clone().

This folds SK_SUPPORT_LEGACY_PICTURE_CLONE through as undefined.

Chrome's not used clone() for a month or two, and we don't use it ourselves.
Don't think Android ever did.

CQ_EXTRA_TRYBOTS=tryserver.skia:Canary-Chrome-Ubuntu13.10-Ninja-x86_64-ToT-Trybot

BUG=skia:
R=reed@google.com, mtklein@google.com, robertphillips@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/620533002
4 files changed