Reapply: "Make instanceof and Object.getPrototypeOf work for proxies,

src/proxy.js

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 42 matching lines @@
   "constructTrap",
 ]
 
 $Proxy.createFunction = function(handler, callTrap, constructTrap) {
   handler.callTrap = callTrap
   handler.constructTrap = constructTrap
   $Proxy.create(handler)
 }
 
 $Proxy.create = function(handler, proto) {
-  if (!IS_SPEC_OBJECT(handler)) throw TypeError
-  if (!IS_SPEC_OBJECT(proto)) proto = $Object.prototype
+  if (!IS_SPEC_OBJECT(handler))
+    throw MakeTypeError("handler_non_object", ["create"])
+  if (!IS_SPEC_OBJECT(proto)) proto = null  // Mozilla does this...
   return %CreateJSProxy(handler, proto)
 }
 
 
 
 
 ////////////////////////////////////////////////////////////////////////////////
 // Builtins
 ////////////////////////////////////////////////////////////////////////////////
 
@@ skipping 48 matching lines @@
       }
     }
   }
   this.defineProperty(name, {
     value: val,
     writable: true,
     enumerable: true,
     configurable: true});
   return true;
 }
+
+function DerivedHasTrap(name) {
+  return !!this.getPropertyDescriptor(name)
+}