Unit tests are occasionally, but not always, failing with "TypeError: Cannot read property 'debounce' of undefined".
Most recent: https://gerrit.wikimedia.org/r/c/mediawiki/extensions/VisualEditor/+/525273 / https://integration.wikimedia.org/ci/job/wmf-quibble-vendor-mysql-hhvm-docker/31646/console
20:52:48 HeadlessChrome 73.0.3683 (Linux 0.0.0) WARN: 'jQuery.Deferred exception: Cannot read property 'debounce' of undefined', 'TypeError: Cannot read property 'debounce' of undefined 20:52:48 at HTMLDocument.<anonymous> (http://localhost:9876/load.php?lang=en&modules=color-picker%2CdataValues%2CdiffMatchPatch%2Cdompurify%7CdataValues.DataValue%2CTimeValue%2Cvalues%7Ceasy-deflate.core%2Cdeflate%7Cext.cite.style%2Cstyles%2CvisualEditor%7Cext.cite.visualEditor.core%2Cdata%2Ctest%7Cext.cx.model%2Csitemapper%2Ctranslation%2Cutil%7Cext.cx.tools.card%2Ccategories%2Cmanager%2Cmtabuse%2Cvalidator%7Cext.cx.translation.loader%2Cprogress%7Cext.cx.util.selection%7Cext.cx.widgets.spinner%7Cext.echo.api%2Cdm%2Cinit%7Cext.echo.dm.tests%7Cext.eventLogging%2Cflow%2CnavigationTiming%2Cthanks%7Cext.eventLogging.debug%7Cext.flow.components%2Cdm%2Ctemplating%2Ctests%2Cui%7Cext.flow.dm.tests%7Cext.flow.jquery.conditionalScroll%2CfindWithParent%7Cext.flow.jquery.findWithParent.tests%7Cext.guidedTour.lib%2Cstyles%7Cext.guidedTour.lib.internal%2Ctests%7Cext.navigationTiming.rumSpeedIndex%7Cext.templateData.test%7Cext.templateDataGenerator.data%7Cext.thanks.images%2Cmobilediff%7Cext.translate.parsers%7Cext.translate.parsers.test%7Cext.translate.special.pagemigration%7Cext.translate.special.pagemigration.test%7Cext.uls.common%2Ci18n%2Cinit%2Clanguagenames%2Cmediawiki%2Cmessages%2Cpreferences%2Ctests%7Cext.visualEditor.articleTarget%2Cbase%2CcheckList%2CcommentAnnotation%2Ccore%2Cdata%2CdesktopArticleTarget%2CdesktopTarget%2Cdiffing%2Cexperimental%2Cicons%2Clanguage%2Cmediawiki%2CmoduleIcons%2CmoduleIndicators%2Cmwalienextension%2Cmwcore%2Cmwextensionmessages%2Cmwextensions%2Cmwformatting%2Cmwgallery%2Cmwimage%2Cmwlanguage%2Cmwlink%2Cmwmeta%2Cmwsave%2Cmwtransclusion%2CprogressBarWidget%2Crebase%2Csanitize%2CsupportCheck%2Cswitching%2CtargetLoader%2CtempWikitextEditorWidget%2Ctrack%2Cve%2Cwelcome%7Cext.visualEditor.core.desktop%7Cext.visualEditor.desktopArticleTarget.init%7Cext.visualEditor.mwextensions.desktop%7Cext.visualEditor.mwimage.core%7CglobeCoordinate.js%7Cjquery.AnimationEvent%2CPurposedCallbacks%2CaccessKeyLabel%2Cajaxdispatcher%2CanimateWithEvent%2CcheckboxShiftClick%2Cclient%2Ccolor%2CcolorUtil%2Ccookie&skin=vector&version=12lc9ha:244:429) 20:52:48 at mightThrow (http://localhost:9876/load.php?lang=en&modules=jquery%7Cmediawiki.base&skin=vector&version=07mxh9n:48:916) 20:52:48 at process (http://localhost:9876/load.php?lang=en&modules=jquery%7Cmediawiki.base&skin=vector&version=07mxh9n:49:589)', undefined