Update FF test config.

.travis.yml

@@ -20,7 +20,7 @@ before_script:
   update-types".' && false)
 script:
 - wct -l chrome
-- wct -l firefox
+- xvfb-run wct -l firefox
 - if [ "${TRAVIS_PULL_REQUEST}" = "false" ]; then travis_wait 30 ./util/travis-sauce-test.sh; fi
 env:
   global:

package.json

@@ -31,7 +31,7 @@
     "polymer-build": "^2.1.1",
     "run-sequence": "^2.2.0",
     "through2": "^2.0.0",
-    "web-component-tester": "^6.5.0"
+    "web-component-tester": "^6.9.0"
   },
   "scripts": {
     "build": "gulp",

test/unit/globals.html

@@ -85,7 +85,10 @@
     // weird safari + selenium globals
     alert: true,
     confirm: true,
-    prompt: true
+    prompt: true,
+
+    // weird FF globals
+    XULElement: true
   };
 
   test('check global leakage', function() {

util/travis-sauce-test.sh

@@ -9,4 +9,4 @@
 # subject to an additional IP rights grant found at http://polymer.github.io/PATENTS.txt
 #
 set -x
-wct -s 'windows 10/microsoftedge@14' -s 'windows 10/microsoftedge@15' -s 'windows 10/microsoftedge@16' -s 'windows 8.1/internet explorer@11' -s 'os x 10.11/safari@9' -s 'macos 10.12/safari@10' -s 'macos 10.13/safari@11' -s 'Linux/chrome@41'
+wct -s 'windows 10/microsoftedge@15' -s 'windows 10/microsoftedge@17' -s 'windows 8.1/internet explorer@11' -s 'os x 10.11/safari@9' -s 'macos 10.13/safari@11' -s 'macos 10.13/safari@12' -s 'Linux/chrome@41' -s 'windows/firefox@62'

wct.conf.json

@@ -10,9 +10,6 @@
           "headless",
           "disable-gpu",
           "no-sandbox"
-        ],
-        "firefox": [
-          "-headless"
         ]
       }
     }