Perf move to using new login.InitFromMetadataOrJSON.
Perf move to using new login.InitFromMetadataOrJSON.

BUG=skia:4591

Review URL: https://codereview.chromium.org/1468203003

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