retain colorspace in blurimagefilter_raster

Bug: skia:8773
Change-Id: Id6c84f1216c6e6dcd455fe57e661bcb734899b86
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/200601
Commit-Queue: Mike Reed <reed@google.com>
Reviewed-by: Mike Klein <mtklein@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
1 file changed