Support for a dart2js `dartDeferredLoader` hook.

pkg/compiler/lib/src/js_emitter/old_emitter/declarations.dart

 // Copyright (c) 2013, 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 dart2js.js_emitter;
 
 /// Enables debugging of fast/slow objects using V8-specific primitives.
 const DEBUG_FAST_OBJECTS = false;
 
 /**
@@ skipping 39 matching lines @@
 const String HOOKS_API_USAGE = """
 // The code supports the following hooks:
 // dartPrint(message):
 //    if this function is defined it is called instead of the Dart [print]
 //    method.
 //
 // dartMainRunner(main, args):
 //    if this function is defined, the Dart [main] method will not be invoked
 //    directly. Instead, a closure that will invoke [main], and its arguments
 //    [args] is passed to [dartMainRunner].
+//
+// dartDeferredLibraryLoader(uri, successCallback, errorCallback):
+//    if this function is defined, it will be called when a deferered library
+//    is loaded. It should load and eval the javascript on uri, and call

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

javascript on uri -> javascript of `uri`

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

Done.

+//    successCallback. If it fails to do so, it should call errorCallback with
+//    an error.
 """;
 
 // Compact field specifications.  The format of the field specification is
 // <accessorName>:<fieldName><suffix> where the suffix and accessor name
 // prefix are optional.  The suffix directs the generation of getter and
 // setter methods.  Each of the getter and setter has two bits to determine
 // the calling convention.  Setter listed below, getter is similar.
 //
 //     00: no setter
 //     01: function(value) { this.field = value; }
 //     10: function(receiver, value) { receiver.field = value; }
 //     11: function(receiver, value) { this.field = value; }
 //
 // The suffix encodes 4 bits using three ASCII ranges of non-identifier
 // characters.
 const FIELD_CODE_CHARACTERS = r"<=>?@{|}~%&'()*";
 const NO_FIELD_CODE = 0;
 const FIRST_FIELD_CODE = 1;
 const RANGE1_FIRST = 0x3c;   //  <=>?@    encodes 1..5
 const RANGE1_LAST = 0x40;
 const RANGE2_FIRST = 0x7b;   //  {|}~     encodes 6..9
 const RANGE2_LAST = 0x7e;
 const RANGE3_FIRST = 0x25;   //  %&'()*+  encodes 10..16
 const RANGE3_LAST = 0x2b;