ci(travis-ci): Move X framebuffer into services

Author: rkaraivanov

.travis.yml

@@ -6,14 +6,14 @@ addons:
       - google-chrome
     packages:
       - google-chrome-stable
+services:
+  - xvfb
 language: node_js
 node_js:
 - '10.12.0'
 before_install:
 - export NG_CLI_ANALYTICS=false
-- export CHROME_BIN=/usr/bin/google-chrome
 - export DISPLAY=:99.0
-- sh -e /etc/init.d/xvfb start
 before_script:
 # more heap mem per https://github.com/angular/angular-cli/issues/12645, https://github.com/npm/npm/issues/12238#issuecomment-367147962
 - export NODE_OPTIONS="--max_old_space_size=4096"