Use WriteVertexData in GrTessellator, remove all DefaultGeoProc structs

The structs were previously used to compute vertex strides, and in a
couple places to do vertex writing (like this). We're moving to get
stride from the GP, and using WriteVertexData to serialize into buffers,
so these aren't needed.

Bug: skia:
Change-Id: If7eb89564e43231633290c8d19b68181e0efa89a
Reviewed-on: https://skia-review.googlesource.com/c/170720
Reviewed-by: Brian Salomon <bsalomon@google.com>
Commit-Queue: Brian Osman <brianosman@google.com>
2 files changed