[svg] Handle std input case for filter subregion calculation

From the spec [1], if any inputs of a filter are one of the standard
inputs (SourceGraphic, FillPaint, etc. -- anything except another
filter), then the default filter primitive subregion is equal to the
filter effect region.

[1] https://www.w3.org/TR/SVG11/filters.html#FilterPrimitiveSubRegion

Bug: skia:10841
Change-Id: I70632e5119861c46c9e48af944d2c7cfdfc3c351
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/354119
Reviewed-by: Florin Malita <fmalita@chromium.org>
Commit-Queue: Tyler Denniston <tdenniston@google.com>
1 file changed