Polymer-based Garden-O-Matic should have a basic results panel

This CL makes it possible to examine failures on Sheriff-O-Matic (the Polymer
version of Garden-O-Matic). Currently, the results panel just lets you select
which test and builder you're interested in. It's not able to display the
actual test results yet.

NOTRY=true

Review URL: https://codereview.chromium.org/349783003

git-svn-id: svn://svn.chromium.org/blink/trunk@177189 bbb929c8-8fbe-4397-9dbb-9b2b20218538