Add lookupInScope to DeclarationMirror.

sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart

Index: sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
diff --git a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
index ae01ea08c5c2c595968bf5568fc61aab40ba4a80..08c243e199632bfc7795b8560da7da090b62c372 100644
--- a/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
+++ b/sdk/lib/_internal/compiler/implementation/mirrors/mirrors_util.dart
@@ -217,3 +217,25 @@ String stripComment(String comment) {
   }
   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;
+}