Split out BlitMask opts into separate cpp files

See https://skia-review.googlesource.com/c/skia/+/727257 for details

Bug: b/40045064
Bug: b/40045066
Change-Id: I2294e49be894d7b470e6a69b4a7ec06ec44439cd
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/736881
Commit-Queue: Brian Osman <brianosman@google.com>
Reviewed-by: Kevin Lubick <kjlubick@google.com>
11 files changed