diff --git a/.travis.dist.yml b/.travis.dist.yml
index 19a1e92b..ac41af7b 100644
--- a/.travis.dist.yml
+++ b/.travis.dist.yml
@@ -32,7 +32,7 @@ before_install:
   - cd ../..
   - composer create-project -n --no-dev --prefer-dist blackboard-open-source/moodle-plugin-ci ci ^2
   - export PATH="$(cd ci/bin; pwd):$(cd ci/vendor/bin; pwd):$PATH"
-  - docker run -d -p 127.0.0.1:4444:4444 --net=host -v /dev/shm:/dev/shm selenium/standalone-firefox:3
+  - docker run -d -p 127.0.0.1:4444:4444 --net=host --shm-size=2g -v $HOME/build/moodle:$HOME/build/moodle selenium/standalone-firefox:2.53.1
 
 install:
   - moodle-plugin-ci install
diff --git a/.travis.yml b/.travis.yml
index 53752ca4..0b943805 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -23,21 +23,20 @@ env:
     - MUSTACHE_IGNORE_NAMES=broken.mustache
     - DB=pgsql
     - MOODLE_BRANCH=master
-    - PROFILE=chrome
 
-install:
+before_install:
   - phpenv config-rm xdebug.ini
   - nvm install 8.9
   - nvm use 8.9
   - make init
-  # Start Selenium Standalone with Chrome/Firefox installed.
-  - docker run -d -p 127.0.0.1:4444:4444 --net=host -v /dev/shm:/dev/shm selenium/standalone-${PROFILE}:3
   # Mimic how a Moodle plugin would be run.
   - cp -R tests/Fixture/moodle-local_travis ../moodle-local_travis
   - export PATH="$(cd bin; pwd):$(cd vendor/bin; pwd):$PATH"
   - export TRAVIS_BUILD_DIR=$(cd ../moodle-local_travis; pwd)
+  # Start Selenium Standalone with Chrome.
+  - docker run -d -p 127.0.0.1:4444:4444 --net=host --shm-size=2g -v $HOME/build/moodle:$HOME/build/moodle selenium/standalone-chrome:3
 
-  # Finally, the standard install step.
+install:
   - moodle-plugin-ci install
 
 script:
@@ -54,14 +53,13 @@ script:
   - moodle-plugin-ci grunt || [ "$MOODLE_BRANCH" != 'master' -a "$MOODLE_BRANCH" != 'MOODLE_38_STABLE' ]
   - moodle-plugin-ci phpdoc
   - moodle-plugin-ci phpunit --coverage-text
-  - moodle-plugin-ci behat --profile $PROFILE
+  - moodle-plugin-ci behat --profile chrome
 
 jobs:
   include:
     - stage: Tests
       addons: skip
       install:
-        - phpenv config-rm xdebug.ini
         - make init
       script:
         - make validate
diff --git a/docs/TravisFileExplained.md b/docs/TravisFileExplained.md
index 93dca445..254edd43 100644
--- a/docs/TravisFileExplained.md
+++ b/docs/TravisFileExplained.md
@@ -68,8 +68,9 @@ before_install:
   - export PATH="$(cd ci/bin; pwd):$(cd ci/vendor/bin; pwd):$PATH"
 # Start Selenium Standalone server with Chrome/Firefox installed. If you
 # prefer to run Behat tests with Chrome profile (see Behat step details below),
-# use selenium/standalone-chrome:3 image instead.
-  - docker run -d -p 127.0.0.1:4444:4444 --net=host -v /dev/shm:/dev/shm selenium/standalone-firefox:3
+# use selenium/standalone-chrome:3 image instead. If you don't run Behat tests,
+# this step is not needed.
+  - docker run -d -p 127.0.0.1:4444:4444 --net=host --shm-size=2g -v $HOME/build/moodle:$HOME/build/moodle selenium/standalone-firefox:2.53.1
 
 # This lists steps that are run for installation and setup.
 install: