Start emitting top-level functions.

lib/compiler/implementation/dart_backend/backend.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.
 
 class BailoutException {
   final String reason;
 
   const BailoutException(this.reason);
 }
 
@@ skipping 25 matching lines @@
     resolvedElements.forEach((element, treeElements) {
       unparseValidator.check(element);
     });
 
     // TODO(antonm): Eventually bailouts will be proper errors.
     void bailout(String reason) {
       throw new BailoutException(reason);
     }
 
     try {
+      StringBuffer sb = new StringBuffer();
       resolvedElements.forEach((element, treeElements) {
-        bailout('I can do nothing right now.');
+        if (!element.isTopLevel()) {
+          bailout('Cannot process non top-level $element');
+        }
+        sb.add(element.parseNode(compiler).unparse());
       });
+      compiler.assembledCode = sb.toString();
     } catch (BailoutException e) {
       compiler.assembledCode = '''
 main() {
   final bailout_reason = "${e.reason}";
 }
 ''';
     }
   }
 
   log(String message) => compiler.log('[DartBackend] $message');
 }