Bug 1656107 - remove FindContentForSubDocument use from nsGlobalWindowOuter. r=farre

Differential Revision: https://phabricator.services.mozilla.com/D98615

dom/base/nsGlobalWindowOuter.cpp

@@ -5148,14 +5148,11 @@ void nsGlobalWindowOuter::FocusOuter(CallerType aCallerType) {
       }
       return;
     }
-    nsCOMPtr<Document> parentdoc = parent->GetDocument();
-    if (!parentdoc) {
-      return;
-    }
-
-    if (Element* frame = parentdoc->FindContentForSubDocument(mDoc)) {
+    if (!bc->IsCached()) {
+      if (Element* frame = bc->GetEmbedderElement()) {
         nsContentUtils::RequestFrameFocus(*frame, canFocus, aCallerType);
       }
+    }
     return;
   }