Merge crrev.com/1151663002 into M44.

Patched nearly cleanly, with some cosmetic conflics in SkPicture.h.

Original change:
  Don't serialize SkPictures in SkPictureShaders when in untrusted mode.
  This requires we "first" add a has-picture bool to SkPictureShader serialized format.
  BUG=chromium:486947, billions and billions of others.
  Review URL: https://codereview.chromium.org/1151663002

NOTREECHECKS=true
NOTRY=true
NOPRESUBMIT=true
TBR=reed@google.com

Review URL: https://codereview.chromium.org/1231433004
3 files changed