Address the remaining review comments on http://chromiumcodereview.appspot.com/9431029.

lib/compiler/implementation/elements/elements.dart

Index: lib/compiler/implementation/elements/elements.dart
diff --git a/lib/compiler/implementation/elements/elements.dart b/lib/compiler/implementation/elements/elements.dart
index b01d25819070b1e1b5b88fb573f5b197268efb42..8b630f28fadc8dfefe69006121a79c036166afbb 100644
--- a/lib/compiler/implementation/elements/elements.dart
+++ b/lib/compiler/implementation/elements/elements.dart
@@ -333,11 +333,17 @@ class PrefixElement extends Element {
 }
 
 class TypedefElement extends Element {
-  Token token;
+  final Token token;
+  Type cachedType;
+
   TypedefElement(SourceString name, Element enclosing, this.token)
-    : super(name, ElementKind.TYPEDEF, enclosing);
+      : super(name, ElementKind.TYPEDEF, enclosing) {
+    cachedType = new InterfaceType(name, this);
+  }
 
   position() => findMyName(token);
+
+  Type computeType(Compiler compiler) => cachedType;
 }
 
 class VariableElement extends Element {