Use ifdef instead of ifndef

Bug: skia:
Change-Id: I9f86f71247379713ffaf14e5c704c2ac4c6f9cbd
Reviewed-on: https://skia-review.googlesource.com/26861
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
1 file changed