Fix minimization function for offset code

The old code depended on a bug to work properly -- namely we could
still access edges that were marked invalid in order to do the
minimization check. Switching to linked lists removes these edges
from the list. The fix is to prioritize moving along edges that are
part of the same contour in the case of two negative results (which
represent an intersection on the testing segment).

Bug: skia:
Change-Id: I6e44e32887faa2f92dddbc204a38ffa2171ea0c6
Reviewed-on: https://skia-review.googlesource.com/143105
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Jim Van Verth <jvanverth@google.com>
1 file changed