[svg] Fix filter effect subregion calculation

Somewhat subtle, but we were improperly handling the override of the
default subregion via the 'width' and 'height' <fe*> attributes.

Simple example: when specifying 'x' but not 'width', previously we
would use the overridden x (subregion.fLeft = boundaries.fLeft;), but
were not updating subregion.fRight based on the new fLeft value.

Bug: skia:10841
Change-Id: I309de4f0cf50a413ea6a0e7605926a3eb6cd94e2
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/404205
Commit-Queue: Tyler Denniston <tdenniston@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
1 file changed