Don't use 'new Function' for lazily initialized getter.

sdk/lib/_internal/compiler/implementation/js_backend/emitter.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of js_backend;
 
 /**
  * A function element that represents a closure call. The signature is copied
  * from the given element.
  */
@@ skipping 311 matching lines @@
 
   String get lazyInitializerFunction {
     String isolate = namer.CURRENT_ISOLATE;
     JavaScriptBackend backend = compiler.backend;
     String cyclicThrow = namer.isolateAccess(backend.cyclicThrowHelper);
     return """
 function(prototype, staticName, fieldName, getterName, lazyValue) {
   var sentinelUndefined = {};
   var sentinelInProgress = {};
   prototype[fieldName] = sentinelUndefined;
-  var getter = new Function("{ return $isolate." + fieldName + ";}");

[floitsch, 2012/11/21 16:58:13]

Unfortunately no.
I'm pretty sure this would make lazily initialized functions much slower.
You need to special case this in the csp-emitter.
2 alternatives: what you just did (but only when emitting csp), or (faster but
more code) passing in the getter as argument to the lazyInitializerFunction.

+  var getter = function() { return ${isolate}[fieldName]; };
   prototype[getterName] = function() {
     var result = $isolate[fieldName];
     try {
       if (result === sentinelUndefined) {
         $isolate[fieldName] = sentinelInProgress;
         try {
           result = $isolate[fieldName] = lazyValue();
         } catch (e) {
           if ($isolate[fieldName] === sentinelInProgress) {
             $isolate[fieldName] = null;
@@ skipping 1391 matching lines @@
 const String HOOKS_API_USAGE = """
 // Generated by dart2js, the Dart to JavaScript compiler.
 // The code supports the following hooks:
 // dartPrint(message)   - if this function is defined it is called
 //                        instead of the Dart [print] method.
 // dartMainRunner(main) - if this function is defined, the Dart [main]
 //                        method will not be invoked directly.
 //                        Instead, a closure that will invoke [main] is
 //                        passed to [dartMainRunner].
 """;