Fix imports for login in grains.

BUG=skia:
TBR=mtklein

Review URL: https://codereview.chromium.org/654843002
Make tree status banner a quarter circle and make it clickable.

This is how the banner looked like before this CL:
http://skia-tree-status.appspot.com/banner-status/

This is how it will look like after this CL (it is clickable as well):
http://skia-tree-status-staging.appspot.com/banner-status/

BUG=skia:3011

Review URL: https://codereview.chromium.org/659473003