Delete deprecated blur filter header

This also deletes the type conversions between the legacy
tile mode and SkTileMode and cleans up the serialization
logic around that just a little bit.

Bug: skia:11230
Change-Id: If404a73e13f42055a0fe7638dcd9f58cf7e9b896
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/368243
Reviewed-by: Robert Phillips <robertphillips@google.com>
7 files changed