encapsulate the gaussian blur as a class

Encapsulate the cpu gaussian blur as a class. This will allow further blur
strategies in the future.

Bug = skia:12338

Change-Id: I846571787e6600832a412ca1753c02c9b760e18c
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/440556
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Herb Derby <herb@google.com>
1 file changed