Enable automated UI testing on Travis CI

.travis.yml

@@ -1,11 +1,14 @@
 sudo: false
+addons:
+  chrome: stable
 language: node_js
 matrix:
   include:
     - node_js: "12"
     - node_js: "10"
       script:
         - ./node_modules/.bin/grunt && istanbul report text && ( cat coverage/lcov.info | $(npm get prefix)/bin/coveralls || true ) && rm -rf coverage
+        - scripts/install-ui-test-dependencies.sh && grunt test-ui
       before_script:
         - npm install -g istanbul coveralls
     - node_js: "8"

scripts/install-ui-test-dependencies.sh

@@ -4,6 +4,6 @@ npm install --no-save \
  wdio-mocha-framework@^0.6.4 \
  wdio-spec-reporter@^0.1.5 \
  webdriverio@^4.14.4 \
- chromedriver@^79.0.0 \
+ chromedriver \
  wdio-browserstack-service@^0.1.19 \
  browserstack-local@^1.4.4