Improved skslc depth tracking

This fixes a class of bugs discovered by fuzzing, in which a very
complicated expression leads to a stack overflow.

Bug: oss-fuzz:15510
Change-Id: Idee6df8bb1dd4ca101bcc0ef21a974c58017f8a8
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/240510
Commit-Queue: Ethan Nicholas <ethannicholas@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
1 file changed