Implement basic code generation for arrow functions

src/v8natives.js

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file relies on the fact that the following declarations have been made
 // in runtime.js:
 // var $Object = global.Object;
 // var $Boolean = global.Boolean;
 // var $Number = global.Number;
 // var $Function = global.Function;
@@ skipping 1730 matching lines @@
   if (!IS_STRING(source) || %FunctionIsBuiltin(func)) {
     var name = %FunctionGetName(func);
     if (name) {
       // Mimic what KJS does.
       return 'function ' + name + '() { [native code] }';
     } else {
       return 'function () { [native code] }';
     }
   }
 
+  if (%FunctionIsArrow(func)) {
+    return source;
+  }
+
   var name = %FunctionNameShouldPrintAsAnonymous(func)
       ? 'anonymous'
       : %FunctionGetName(func);
   var head = %FunctionIsGenerator(func) ? 'function* ' : 'function ';
   return head + name + source;
 }
 
 
 function FunctionToString() {
   return FunctionSourceString(this);
@@ skipping 104 matching lines @@
   %SetCode($Function, FunctionConstructor);
   %AddNamedProperty($Function.prototype, "constructor", $Function, DONT_ENUM);
 
   InstallFunctions($Function.prototype, DONT_ENUM, $Array(
     "bind", FunctionBind,
     "toString", FunctionToString
   ));
 }
 
 SetUpFunction();