Add lookupInScope to DeclarationMirror.

sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.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 mirrors_util;
 
 import 'dart:collection' show Queue, IterableBase;
 
 // TODO(rnystrom): Use "package:" URL (#4968).
 import 'mirrors.dart';
@@ skipping 199 matching lines @@
         //      * Foo
         //      */
         // as "\nFoo\n" and not as "\nFoo\n     ".
         sb.write(line);
       }
     }
     return sb.toString();
   }
   throw new ArgumentError('Invalid comment $comment');
 }
+
+/**
+ * Looks up [name] in the scope [declaration].
+ *
+ * For methods and constructors, the scope includes the parameters.
+ *
+ * If [name] is of the form [: a.b.c :], [:a:] is looked up in the scope of
+ * [declaration], [:b:] is looked up in the scope of [:a:], and finally [:c:] is
+ * looked up in the scope of [:b:].
+ */
+DeclarationMirror lookupQualifiedInScope(DeclarationMirror declaration,
+                                         String name) {
+  // TODO(johnniwinther): Support lookup of constructors using the [:new Foo:]
+  // syntax.
+  for (String part in name.split('.')) {
+    if (declaration == null) {

[Andrei Mouravski, 2013/07/01 17:46:26]

Nit: One line this?

[Johnni Winther, 2013/07/03 05:47:57]

Done.

+      return null;
+    }
+    declaration = declaration.lookupInScope(part);
+  }
+  return declaration;
+}