Thread picture version through to SkReadBuffer.

This will let code outside SkPicture* fork its read code based on the picture version.

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

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/214413008

git-svn-id: http://skia.googlecode.com/svn/trunk@13984 2bbb7eff-a529-9590-31e7-b0007b416f81
6 files changed