Move SkDeferredDisplayList.h into include\core (take 2)

Clients will need official access to this class for the compilation iterator.

This CL also hides some of the cruft we don't want exposed.

Bug: skia:9455
Change-Id: I696c058f1c409fb459229552fbbdd935ec112358
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/272643
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Robert Phillips <robertphillips@google.com>
13 files changed