Remove picture pre-allocation from SkPictureRecorder

Remove picture pre-allocation from SkPictureRecorder

This CL improves the separation of the SkPicture and SkPictureRecord classes. It delays creation of the SkPicture (in SkPictureRecorder) until recording is actually completed. To accomplish this the SkRecord-derived classes now get SkPathHeap and SkPictureContentInfo members that are absorbed by the SkPicture when it is constructed.

As an ancillary change, this CL also moves the SkPictureContentInfo object from SkPicture to SkPicturePlayback. This is intended to centralize all the data in the SkPicturePlayback object.

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

Author: robertphillips@google.com

Review URL: https://codereview.chromium.org/324293004