handle conic underflow calc

w0 and w2 can both be non-zero, but w2*w0 can be zero -- unless we promote to doubles

Bug: oss-fuzz:6506
Change-Id: Id0716e22e1d989d2eb6d86417575cf917a31cb89
Reviewed-on: https://skia-review.googlesource.com/109480
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Mike Reed <reed@google.com>
1 file changed