Convert the `OverlayManager` class to use private fields/methods
Convert the `OverlayManager` class to use private fields/methods

Snuffleupagus/pdf.js,showpad/mozilla-pdf.js,showpad/mozilla-pdf.js,Shoobx/pdf.js,Snuffleupagus/pdf.js,nawawi/pdf.js,Shoobx/pdf.js,nawawi/pdf.js,nawawi/pdf.js,Snuffleupagus/pdf.js,timvandermeij/pdf.js,timvandermeij/pdf.js,Shoobx/pdf.js,mozilla/pdf.js,showpad/mozilla-pdf.js,timvandermeij/pdf.js,mozilla/pdf.js,mozilla/pdf.js