Count the correct number of pos using text encoding.

Otherwise, the following will crash:

out/ASAN/dm --config t8888 --verbose --src gm -m skbug_5321

Bug: skia:
Change-Id: I9b1d3412b9695b0fbd8a9afb0e6d3ae7159aeee6
Reviewed-on: https://skia-review.googlesource.com/123750
Commit-Queue: Ben Wagner <bungeman@google.com>
Reviewed-by: Ben Wagner <bungeman@google.com>
Auto-Submit: Yuqian Li <liyuqian@google.com>
1 file changed