Deprecate SkPicture::clone().

Chrome will need -DSK_SUPPORT_LEGACY_PICTURE_CLONE.

This removes the modes from our tools that use clone().  No
bots run these.  DM used clone() in a way that we can just
share the picture now.

I plan to bring back the ability to test multithreaded
picture rendering soon.

BUG=skia:2378
R=robertphillips@google.com, mtklein@google.com, bsalomon@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/338633011
17 files changed