gm: Fix eror in textToGlyphs/getXPos

Change-Id: I6f588f1268cf79eb251a6819d306e423c8b8f53a
Reviewed-on: https://skia-review.googlesource.com/c/178264
Commit-Queue: Hal Canary <halcanary@google.com>
Commit-Queue: Herb Derby <herb@google.com>
Auto-Submit: Hal Canary <halcanary@google.com>
Reviewed-by: Herb Derby <herb@google.com>
1 file changed