First pass at splitting out SkPictureRecord from SkPicture

This patch begins the process of splitting apart SkPicture, SkPicturePlayback and SkPictureRecord.

This is still a bit messy. In a follow up CL I hope to delay the creation of SkPictureRecorder's SkPicture until endRecording time.

R=reed@google.com, mtklein@google.com

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/318763004
4 files changed