[svg] Add 'filter' presentation attribute and parsing

Not yet used by anything.

Bug: skia:10841
Change-Id: I6ed0a434cf670d73f06eaf0bbfe70d727ffe4950
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/330617
Commit-Queue: Tyler Denniston <tdenniston@google.com>
Reviewed-by: Florin Malita <fmalita@chromium.org>
8 files changed