Trying to move derived get trap from builtins to global context.

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 45 matching lines @@
 $Proxy.createFunction = function(handler, callTrap, constructTrap) {
   handler.callTrap = callTrap
   handler.constructTrap = constructTrap
   $Proxy.create(handler)
 }
 
 $Proxy.create = function(handler, proto) {
   if (!IS_SPEC_OBJECT(proto)) proto = $Object.prototype
   return %CreateJSProxy(handler, proto)
 }
+
+
+
+
+////////////////////////////////////////////////////////////////////////////////
+// Builtins
+////////////////////////////////////////////////////////////////////////////////
+
+function DerivedGetTrap(receiver, name) {
+  var desc = this.getPropertyDescriptor(name)
+  if (IS_UNDEFINED(desc)) { return desc; }
+  if ('value' in desc) {
+    return desc.value
+  } else {
+    if (IS_UNDEFINED(desc.get)) { return desc.get; }
+    return desc.get.call(receiver)  // The proposal says so...
+  }
+}