Bug 1656107 - remove obsolete comment from nsGlobalWindowOuter. r=farre

The code this comment refers to was changed/removed at some point.

Differential Revision: https://phabricator.services.mozilla.com/D98616

dom/base/nsGlobalWindowOuter.cpp

@@ -5123,9 +5123,6 @@ void nsGlobalWindowOuter::FocusOuter(CallerType aCallerType) {
     return;
   }
 
-  // Don't look for a presshell if we're a root chrome window that's got
-  // about:blank loaded.  We don't want to focus our widget in that case.
-  // XXXbz should we really be checking for IsInitialDocument() instead?
   RefPtr<BrowsingContext> parent;
   BrowsingContext* bc = GetBrowsingContext();
   if (bc) {