Revert[2] "Change SkCanvas to *not* inherit from SkRefCnt"

Changes over original:
- conditionalize ownership in SkPictureRecorder
- conditionalize ownership in SkCanvasStateUtils

This reverts commit b613c266df48cf45296ecc23d1bd7098c84bb7ba.

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=4742

Change-Id: Ib25514d6f546c69b6650b5c957403b04f7380dc2
Reviewed-on: https://skia-review.googlesource.com/4742
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Mike Reed <reed@google.com>
33 files changed