Don't store clipped x which could break edge order

We only need to clip a temporary x to ensure that we don't blit
beyond clip. Storing such clipped x is problematic because it
may make our edges unsorted.

The added unit test would fail without this fix.

Bug: skia:6947
Change-Id: I6c21d7c7c097e50fef18ab151921d6c07c089318
Reviewed-on: https://skia-review.googlesource.com/33420
Commit-Queue: Yuqian Li <liyuqian@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
2 files changed