Support parsing of enums in dart2js.

sdk/lib/_internal/compiler/implementation/scanner/listener.dart

Index: sdk/lib/_internal/compiler/implementation/scanner/listener.dart
diff --git a/sdk/lib/_internal/compiler/implementation/scanner/listener.dart b/sdk/lib/_internal/compiler/implementation/scanner/listener.dart
index 2b69193e011371e886748ea8cb8d1a296b6dd537..0965c5d1aff0ecf6bf5060e361234e0d437e604f 100644
--- a/sdk/lib/_internal/compiler/implementation/scanner/listener.dart
+++ b/sdk/lib/_internal/compiler/implementation/scanner/listener.dart
@@ -72,6 +72,12 @@ class Listener {
                            Token endToken) {
   }
 
+  void beginEnum(Token enumKeyword) {
+  }
+
+  void endEnum(Token enumKeyword, Token endBrace, int count) {
+  }
+
   void beginExport(Token token) {
   }
 
@@ -842,6 +848,12 @@ class ElementListener extends Listener {
                              isDeferred: isDeferred));
   }
 
+  void endEnum(Token enumKeyword, Token endBrace, int count) {
+    NodeList names = makeNodeList(count, enumKeyword.next.next, endBrace, ",");
+    Identifier name = popNode();
+    pushNode(new Enum(enumKeyword, name, names));
+  }
+
   void endExport(Token exportKeyword, Token semicolon) {
     NodeList combinators = popNode();
     StringNode uri = popNode();