Refactor SkPoint reading for MakeFromBuffer
Refactor SkPoint reading for MakeFromBuffer

Now that all the SubRun types have been converted over to use
the bulk point API. The common code can be extracted and shared.

Change-Id: I2a5a515f496291c91a5ae41112f187ee9cec0fd3
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/566559
Commit-Queue: Herb Derby <9e12a3d2bbf73546e47cc9958f6ba8f3215b7eaf@google.com>
Reviewed-by: Robert Phillips <95e8ac5504948c7bf91b22c16a8dbb7ae7c66bfd@google.com>

google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia,google/skia