chore(travis): use headless Chrome in tests

Closes angular#444

Author: gkalpak

.travis.yml

@@ -11,13 +11,9 @@ cache:
   directories:
     - "$HOME/.npm"
 
-before_install:
-  - export DISPLAY=":99.0"
-  - sh -e /etc/init.d/xvfb start
-
 install:
   - npm install
 
 script:
-  - npm run test-single-run
-  - (npm start > /dev/null &) && npm run protractor
+  - npm run test-single-run -- --browsers ChromeHeadless
+  - (npm start > /dev/null &) && npm run protractor -- --capabilities.chromeOptions.args headless

e2e-tests/protractor.conf.js

@@ -8,7 +8,7 @@ exports.config = {
   ],
 
   capabilities: {
-    'browserName': 'chrome'
+    browserName: 'chrome'
   },
 
   baseUrl: 'http://localhost:8000/',