Deal with the JS helper separately from the 'native' keyword.

lib/compiler/implementation/patch_parser.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.
 
 #library("patchparser");
 #import("dart:uri");
 
 #import("tree/tree.dart", prefix: "tree");
 #import("leg.dart", prefix: 'leg');  // CompilerTask, Compiler.
 #import("apiimpl.dart");
@@ skipping 12 matching lines @@
    */
   void patchLibrary(Uri patchUri, LibraryElement library) {
     leg.Script script = compiler.readScript(patchUri, null);
     CompilationUnitElement compilationUnit =
         new CompilationUnitElement(script, library);
     library.addCompilationUnit(compilationUnit);
     LinkBuilder<tree.ScriptTag> imports = new LinkBuilder<tree.ScriptTag>();
     compiler.withCurrentElement(compilationUnit, () {
       // This patches the elements of the patch library into [library].
       // Injected elements are added directly under the compilation unit.
-      // Patche elements are stored on the patched functions or classes.
+      // Patch elements are stored on the patched functions or classes.
       scanLibraryElements(compilationUnit, imports);
     });
     // After scanning declarations, we handle the import tags in the patch.
     // TODO(lrn): These imports end up in the original library and are in
     // scope for the original methods too. This should be fixed.
     for (tree.ScriptTag tag in imports.toLink()) {
       if (tag.isSource()) {
         Uri resolved = patchUri.resolve(tag.argument.dartString.slowToString());
         compiler.scanner.sourceTagInLibrary(tag, resolved, library);
       } else {
@@ skipping 235 matching lines @@
     }
   }
 
   void addMember(Element element) {
     if (isMemberPatch || (isClassPatch && element is ClassElement)) {
       element.addMetadata(popNode());
     }
     super.addMember(element);
   }
 }