Allow native classes to mixin behavior from an ordinary Dart class.

sdk/lib/_internal/compiler/implementation/js_backend/native_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;
 
 class NativeEmitter {
 
   CodeEmitterTask emitter;
   CodeBuffer nativeBuffer;
@@ skipping 83 matching lines @@
   String get defineNativeClassFunction {
     return """
 function(cls, desc) {
   var fields = desc[''];
   var fields_array = fields ? fields.split(',') : [];
   for (var i = 0; i < fields_array.length; i++) {
     ${emitter.currentGenerateAccessorName}(fields_array[i], desc);
   }
   var hasOwnProperty = Object.prototype.hasOwnProperty;
   for (var method in desc) {
-    if (method) {  """/* Short version of: if (method != '') */"""
+    if (method) {

[kasperl, 2013/01/24 11:06:54]

I removed this comment because the newline after the last """ is consumed so the
emitted code looks weird.

       if (hasOwnProperty.call(desc, method)) {
         $dynamicName(method)[cls] = desc[method];
       }
     }
   }
 }""";
   }
 
   bool isNativeGlobal(String quotedName) {
     return identical(quotedName[1], '@');
@@ skipping 422 matching lines @@
       if (emitter.compiler.enableMinification) targetBuffer.add(';');
       targetBuffer.add(js.prettyPrint(
           new js.ExpressionStatement(init), compiler));
       targetBuffer.add('\n');
     }
 
     targetBuffer.add(nativeBuffer);
     targetBuffer.add('\n');
   }
 }