Bug 1579515 - Fix Megabar hidden-focus behaviour. r=dao

Differential Revision: https://phabricator.services.mozilla.com/D45074

--HG--
extra : moz-landing-system : lando

browser/components/urlbar/UrlbarInput.jsm

@@ -825,6 +825,7 @@ class UrlbarInput {
    */
   removeHiddenFocus() {
     this.textbox.classList.remove("hidden-focus");
+    this.startLayoutBreakout();
   }
 
   // Getters and Setters below.