Fix point selection for both big and small scales.
Fix point selection for both big and small scales.

BUG=skia:

Review URL: https://codereview.chromium.org/1421713005

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