The security patches was merged right now, but now the MobileFrontendHooksTest::testOnBeforePageDisplay test set is failing:
```
18:08:13 There were 9 failures:
18:08:13
18:08:13 1) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #0 (true, true, true, true, true, array('a', '502-13'), 1, true, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 2) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #1 (true, false, true, false, false, array('a', '502-13'), 0, true, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 3) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #2 (false, true, true, true, true, array('a', '502-13'), 0, true, true)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 4) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #3 (false, false, true, false, false, array('a', '502-13'), 0, true, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 5) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #4 (true, true, false, true, true, array(), 1, false, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 6) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #5 (true, false, false, false, false, array(), 0, false, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 7) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #6 (false, true, false, true, true, array(), 0, false, true)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 8) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #7 (false, false, false, false, false, array(), 0, false, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
18:08:13
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/extensions/MobileFrontend/tests/phpunit/MobileFrontend.hooksTest.php:77
18:08:13 /mnt/jenkins-workspace/workspace/mediawiki-extensions-hhvm/src/tests/phpunit/MediaWikiTestCase.php:354
18:08:13
18:08:13 9) MobileFrontendHooksTest::testOnBeforePageDisplay with data set #8 (false, false, false, false, true, array(), 0, false, false)
18:08:13 in desktop view the cookie vary header should never be set
18:08:13 Failed asserting that true matches expected false.
```
Possible related https://phabricator.wikimedia.org/rMWaf3b10287e4b4de8360ea57c400c7b8ed71596a1