SkData need not be a Flattenable, since it does not need subclass/factories

BUG=
R=mtklein@google.com

Review URL: https://codereview.chromium.org/26928002

git-svn-id: http://skia.googlecode.com/svn/trunk/src@11754 2bbb7eff-a529-9590-31e7-b0007b416f81
3 files changed