--- a/caps/nsScriptSecurityManager.cpp
+++ b/caps/nsScriptSecurityManager.cpp
@@ -1207,22 +1207,16 @@ nsScriptSecurityManager::doGetObjectPrin
 NS_IMETHODIMP
 nsScriptSecurityManager::CanCreateWrapper(JSContext *cx,
                                           const nsIID &aIID,
                                           nsISupports *aObj,
                                           nsIClassInfo *aClassInfo)
 {
 // XXX Special case for Exception ?
 
-    uint32_t flags;
-    if (aClassInfo && NS_SUCCEEDED(aClassInfo->GetFlags(&flags)) &&
-        (flags & nsIClassInfo::DOM_OBJECT)) {
-        return NS_OK;
-    }
-
     // We give remote-XUL whitelisted domains a free pass here. See bug 932906.
     JS::Rooted<JS::Realm*> contextRealm(cx, JS::GetCurrentRealmOrNull(cx));
     MOZ_RELEASE_ASSERT(contextRealm);
     if (!xpc::AllowContentXBLScope(contextRealm)) {
         return NS_OK;
     }
 
     if (nsContentUtils::IsCallerChrome()) {

--- a/js/xpconnect/src/XPCWrappedNativeJSOps.cpp
+++ b/js/xpconnect/src/XPCWrappedNativeJSOps.cpp
@@ -262,22 +262,17 @@ DefinePropertyIfFound(XPCCallContext& cc
 
                 if (classInfo) {
                     nsresult rv = classInfo->GetFlags(&flags);
                     if (NS_FAILED(rv))
                         return Throw(rv, ccx);
                 }
             }
 
-            bool overwriteToString = !(flags & nsIClassInfo::DOM_OBJECT)
-                || Preferences::GetBool("dom.XPCToStringForDOMClasses", false);
-
-            if(id == xpccx->GetStringID(XPCJSContext::IDX_TO_STRING)
-                && overwriteToString)
-            {
+            if (id == xpccx->GetStringID(XPCJSContext::IDX_TO_STRING)) {
                 call = XPC_WN_Shared_ToString;
                 name = xpccx->GetStringName(XPCJSContext::IDX_TO_STRING);
             } else if (id == xpccx->GetStringID(XPCJSContext::IDX_TO_SOURCE)) {
                 call = XPC_WN_Shared_ToSource;
                 name = xpccx->GetStringName(XPCJSContext::IDX_TO_SOURCE);
             } else if (id == SYMBOL_TO_JSID(
                                JS::GetWellKnownSymbol(ccx, JS::SymbolCode::toPrimitive)))
             {