
This is a partial roll-forward of c/106190 This replaces all loads of iron-test-helpers with a load of a file that wraps it, and adds that file to test files that do not currently load iron-test-helpers. A future CL will also install polymer-resin via common-test-helpers.html. I tested by running $ WCT_ARGS="-l chrome" ./polygerrit-ui/app/run_test.sh Change-Id: Ifb3cd2c8db13d724f57e56e7e78045470d103a43