[svg] Cleanup: drop the presentation attribute SkPaint cache

Instead of attempting to keep fill & stroke SkPaints synchronized with
the current presentation attributes throughout the DAG walk, build the
SkPaints on the fly, only when needed.

This simplifies presentation attribute handling and enables further
/future refactoring.

Change-Id: I3791b4244530644e7e4b983d93b3c966ea7a1b22
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/355096
Commit-Queue: Florin Malita <fmalita@chromium.org>
Commit-Queue: Florin Malita <fmalita@google.com>
Reviewed-by: Tyler Denniston <tdenniston@google.com>
5 files changed