Don't clear HasDirAutoSet on a <bdi>. Bug 838489, r=ehsan

content/html/content/src/nsGenericHTMLElement.cpp

@@ -823,11 +823,11 @@ nsGenericHTMLElement::AfterSetAttr(int32_t aNamespaceID, nsIAtom* aName,
       } else {
         ClearHasValidDir();
         ClearHasFixedDir();
-        ClearHasDirAuto();
-        ClearHasDirAutoSet();
         if (NodeInfo()->Equals(nsGkAtoms::bdi)) {
           SetHasDirAuto();
         } else {
+          ClearHasDirAuto();
+          ClearHasDirAutoSet();
           dir = RecomputeDirectionality(this, aNotify);
         }
       }