Fix shadow directional light bounds.

The shadowRec bounds code didn't handle directional lights, that's now
fixed. Also fixes normalization of the light direction -- it was only
using two components, it should use all three.

Bug: skia:10781
Change-Id: Ia7d39c5187f976627d017ac4abecbe1d1dc62712
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/345126
Reviewed-by: Brian Osman <brianosman@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
5 files changed