Support for a dart2js `dartDeferredLoader` hook.

sdk/lib/_internal/compiler/js_lib/preambles/d8.js

 // Copyright (c) 2014, 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.
 
 // Javascript preamble, that lets the output of dart2js run on V8's d8 shell.
 
 // Node wraps files and provides them with a different `this`. The global
 // `this` can be accessed through `global`.
 
 var self = this;
@@ skipping 261 matching lines @@
   self.dartMainRunner = function(main, args) {
     // Initialize.
     var action = function() { main(args); }
     eventLoop(action);
   };
   self.setTimeout = addTimer;
   self.clearTimeout = cancelTimer;
   self.setInterval = addInterval;
   self.clearInterval = cancelTimer;
   self.scheduleImmediate = addTask;
   self.self = self;

[floitsch, 2015/02/25 16:00:00]

Create a "section" (with a comment).

Keep 'self.self = self' last (or move it to the very top).

[sigurdm, 2015/02/26 13:19:05]

Done.

+  self.dartDeferredLibraryLoader =
+    function(uri, successCallback, errorCallback) {
+      try {
+        (new Function(load(uri)))();

[Lasse Reichstein Nielsen, 2015/02/26 08:44:09]

What is the "new Function" supposed to do?
I think "load" will load *and* execute the script in the top-level scope, and
then return undefined.
You are basically loading it, and then doing "new Function(undefined)()".

[sigurdm, 2015/02/26 13:19:05]

Yes, I realized that this morning also.

+        successCallback();
+      } catch (error) {
+        errorCallback(error);
+      }
+    };
 })(self);