This is pretty much just refactoring, condensing the virtual APIs of
PathTessellator and StrokeTessellator to not require exposing
PatchWriter. Once landed, this makes it easier to move PatchWriter to
a template where each Tessellator subclass has a different instantation.
Bug: skia:13012
Change-Id: I1211a707f3e6ac6b3543cf17a3d3af0372221ce4
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/517978
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Michael Ludwig <michaelludwig@google.com>
35553cd3a7