add support for package: to the editor

compiler/java/com/google/dart/compiler/UrlLibrarySource.java

Index: compiler/java/com/google/dart/compiler/UrlLibrarySource.java
===================================================================
--- compiler/java/com/google/dart/compiler/UrlLibrarySource.java	(revision 7713)
+++ compiler/java/com/google/dart/compiler/UrlLibrarySource.java	(working copy)
@@ -1,4 +1,4 @@
-// Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
+// 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.
 package com.google.dart.compiler;
@@ -58,6 +58,13 @@
           uri = shortUri;
         }
       }
+      if (SystemLibraryManager.isPackageUri(uri)){
+        URI fileUri = systemLibraryManager.resolveDartUri(uri);
+        if (fileUri != null){
+          uri = fileUri;
+        }
+       
+      }
       return new UrlLibrarySource(uri, systemLibraryManager);
     } catch (Throwable e) {
       return null;