Do not set record to empty if it's already computed

Otherwise, the following test will fail:

./out/Debug/dm --config t8888 -m strokes_round

Bug: skia:
Change-Id: Ifc618fc42c6f387eae7b6aadd8424001c3e1464e
Reviewed-on: https://skia-review.googlesource.com/113440
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
1 file changed