fix nextContour bug

Calling nextContour() needs to ensure that we've already measured the "current" one.

Bug: skia:
Change-Id: I501c26d0b068028d67103888f06ec89125a5407a
Reviewed-on: https://skia-review.googlesource.com/114692
Reviewed-by: Cary Clark <caryclark@google.com>
Commit-Queue: Mike Reed <reed@google.com>
2 files changed