Make arguments to Location.assign() and .replace() non-optional

Source/core/frame/Location.idl

Index: Source/core/frame/Location.idl
diff --git a/Source/core/frame/Location.idl b/Source/core/frame/Location.idl
index da81ecff9f585b6d5781ef7040e8320a339d950d..5ce29901ece1c12697f524c54e386b17d61a3071 100644
--- a/Source/core/frame/Location.idl
+++ b/Source/core/frame/Location.idl
@@ -36,8 +36,8 @@
     // problem, since that allows tracking navigation.
     [SetterCallWith=ActiveWindow&FirstWindow, DoNotCheckSecurity=Setter, Unforgeable] attribute DOMString href;
 
-    [CallWith=ActiveWindow&FirstWindow, DoNotCheckSecurity, Unforgeable, ReadOnly, PerWorldBindings, ActivityLogging=ForIsolatedWorlds] void assign([Default=Undefined] optional DOMString url);
-    [CallWith=ActiveWindow&FirstWindow, DoNotCheckSecurity, Unforgeable, ReadOnly, PerWorldBindings, ActivityLogging=ForIsolatedWorlds] void replace([Default=Undefined] optional DOMString url);
+    [CallWith=ActiveWindow&FirstWindow, DoNotCheckSecurity, Unforgeable, ReadOnly, PerWorldBindings, ActivityLogging=ForIsolatedWorlds] void assign(DOMString url);
+    [CallWith=ActiveWindow&FirstWindow, DoNotCheckSecurity, Unforgeable, ReadOnly, PerWorldBindings, ActivityLogging=ForIsolatedWorlds] void replace(DOMString url);
     [CallWith=ActiveWindow, Unforgeable, ReadOnly] void reload();
 
     // URI decomposition attributes