ES6: Adding support for size to Set and Map

src/v8natives.js

 // Copyright 2012 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 @@
     var key = functions[i];
     var f = functions[i + 1];
     %FunctionSetName(f, key);
     %FunctionRemovePrototype(f);
     %SetProperty(object, key, f, attributes);
     %SetNativeFlag(f);
   }
   %ToFastProperties(object);
 }
 
+
+// Helper function to install a getter only property.
+function InstallGetter(object, name, getter) {
+  %FunctionSetName(getter, name);
+  %FunctionRemovePrototype(getter);
+  %DefineOrRedefineAccessorProperty(object, name, getter, null, DONT_ENUM);
+  %SetNativeFlag(getter);
+}
+
+
 // Prevents changes to the prototype of a built-infunction.
 // The "prototype" property of the function object is made non-configurable,
 // and the prototype object is made non-extensible. The latter prevents
 // changing the __proto__ property.
 function SetUpLockedPrototype(constructor, fields, methods) {
   %CheckIsBootstrapping();
   var prototype = constructor.prototype;
   // Install functions first, because this function is used to initialize
   // PropertyDescriptor itself.
   var property_count = (methods.length >> 1) + (fields ? fields.length : 0);
@@ skipping 1594 matching lines @@
 
 function SetUpFunction() {
   %CheckIsBootstrapping();
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetUpFunction();