Beginning support for library prefixes in the dart API.

runtime/bin/builtin_nolib.cc

 // 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.
 
 #include <stdio.h>
 
 #include "include/dart_api.h"
 
 #include "bin/builtin.h"
 #include "bin/dartutils.h"
@@ skipping 43 matching lines @@
       SetupLibrary(library, id);
     }
   }
   DART_CHECK_VALID(library);
   return library;
 }
 
 
 void Builtin::ImportLibrary(Dart_Handle library, BuiltinLibraryId id) {
   Dart_Handle imported_library = LoadLibrary(id);
+  Dart_Handle prefix = Dart_NewString("");
   // Import the library into current library.
-  DART_CHECK_VALID(Dart_LibraryImportLibrary(library, imported_library));
+  DART_CHECK_VALID(Dart_LibraryImportLibrary(library,
+                                             imported_library,
+                                             prefix));
 }