Bug 1260496 - get rid of CacheChildren for application accessible, r=marcoz

accessible/base/DocManager.cpp

@@ -60,9 +60,6 @@ DocManager::GetDocAccessible(nsIDocument* aDocument)
   if (!aDocument)
     return nullptr;
 
-  // Ensure CacheChildren is called before we query cache.
-  ApplicationAcc()->EnsureChildren();
-
   DocAccessible* docAcc = GetExistingDocAccessible(aDocument);
   if (docAcc)
     return docAcc;