Switch GPU blur code over to using GrRecordingContext

This is split out of: https://skia-review.googlesource.com/c/skia/+/191287 (Move DrawingManager to RecordingContext)

Change-Id: I305249f1e63bd4720264b0531733a219c79fe10a
Reviewed-on: https://skia-review.googlesource.com/c/192686
Auto-Submit: Robert Phillips <robertphillips@google.com>
Commit-Queue: Greg Daniel <egdaniel@google.com>
Reviewed-by: Greg Daniel <egdaniel@google.com>
10 files changed