message: ci: remove redundant `start-xvfb` step
  Since the jobs that need Xvfb use `*-browser` CircleCI docker
  image flavors (e.g. `circleci/node:10.12-browsers`), which automatically
  start Xvfb.
  PR Close
diff: @@ -33,24 +33,18 @@ var_6: &job_defaults
  docker:
  - image: *default_docker_image
  -var_7: &start-xvfb
  - run:
  - name: Running X virtual framebuffer
  - command: Xvfb :99 -screen 0 1280x1024x24
  - background: true
  -
  # After checkout, rebase on top of master.
  # Similar to travis behavior, but not quite the same.
  # See https://discuss.circleci.com/t/1662
  -var_8: &post_checkout
  +var_7: &post_checkout
  post: git pull --ff-only origin "refs/pull/${CI_PULL_REQUEST//*pull\//}/merge"
  -var_9: &yarn_install
  +var_8: &yarn_install
  run:
  name: Running Yarn install
  command: yarn install --frozen-lockfile --non-interactive
  -var_10: &setup_circleci_bazel_config
  +var_9: &setup_circleci_bazel_config
  run:
  name: Setting up CircleCI bazel configuration
  command: sudo cp .circleci/bazel.rc /etc/bazel.bazelrc
  @@ -163,7 +157,6 @@ jobs:
  - restore_cache:
  key: *cache_key
  - *define_env_vars
  - - *start-xvfb
  # Build aio
  - run: yarn --cwd aio build --progress=false
  # Lint the code
  @@ -192,7 +185,6 @@ jobs:
  - restore_cache:
  key: *cache_key
  - *define_env_vars
  - - *start-xvfb
  # Deploy angular.io to production (if necessary)
  - run: setPublicVar CI_STABLE_BRANCH "$(npm info @angular/core dist-tags.latest | sed -r 's/^\s*([0-9]+\.[0-9]+)\.[0-9]+.*$/\1.x/')"
  - run: yarn --cwd aio deploy-production
  @@ -210,7 +202,6 @@ jobs:
  - attach_workspace:
  at: dist
  - *define_env_vars
  - - *start-xvfb
  # Build aio (with local Angular packages)
  - run: yarn --cwd aio build-local --progress=false
  # Run PWA-score tests
  @@ -251,7 +242,6 @@ jobs:
  - attach_workspace:
  at: dist
  - *define_env_vars
  - - *start-xvfb
  # Install root
  - *yarn_install
  # Install aio
  @@ -272,7 +262,6 @@ jobs:
  - attach_workspace:
  at: dist
  - *define_env_vars
  - - *start-xvfb
  # Install root
  - *yarn_install
  # Install aio
  @@ -311,7 +300,6 @@ jobs:
  - restore_cache:
  key: *cache_key
  - *define_env_vars
  - - *start-xvfb
  - run: yarn install --cwd aio --frozen-lockfile --non-interactive
  - run:
  name: Wait for preview and run tests
  @@ -371,7 +359,6 @@ jobs:
  - attach_workspace:
  at: dist
  - *define_env_vars
  - - *start-xvfb
  - run: ./integration/run_tests.sh
  # This job updates the content of repos like github.com/angular/core-builds
  @@ -415,7 +402,6 @@ jobs:
  - restore_cache:
  key: *cache_key
  - *define_env_vars
  - - *start-xvfb
  - run:
  name: Run tests against the deployed apps
  command: ./aio/scripts/test-production.sh $CI_AIO_MIN_PWA_SCORE
  