Add WCT Sauce Labs config

This change is required by Gerrit CI (Ide6f2ac17) for automatic change
verification. It is disabled by default, but can also be used locally
(instead of using local browsers).

Change-Id: I0c1283227192186f12c07e3529cdab3f2a07bfa0

polygerrit-ui/app/polygerrit_wct_tests.py

@@ -87,6 +87,19 @@ class PolyGerritWctTests(unittest.TestCase):
           # seems to still work, so there's that.
           'skipSeleniumInstall': True,
         },
+        'sauce': {
+          # Disabled by default in order to run local tests only.
+          # Run it with (saucelabs.com account required; free for open source):
+          # WCT_ARGS='--plugin sauce' buck test --no-results-cache --include web
+          'disabled': True,
+          'browsers': [
+            'Linux/chrome',
+            'OS X 10.11/chrome',
+            'Windows 10/chrome',
+            'Linux/firefox',
+            'OS X 10.11/safari',
+          ],
+        },
       },
     })