[perf] - Fix tick mark units depending on scale of x-axis.
[perf] - Fix tick mark units depending on scale of x-axis.

Screenshot:
   https://screenshot.googleplex.com/5iojetfSXWy.png

Bug: skia:9138
Change-Id: I6683f7dc2bbc3ea286e2180b3f833fd6779eddee
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/217517
Reviewed-by: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>
Commit-Queue: Joe Gregorio <b9cf2471ff6d33504cafe8e6f356b732b2cadced@google.com>

google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot,google/skia-buildbot