Unbreak the parser.

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

Index: dart/lib/compiler/implementation/scanner/listener.dart
diff --git a/dart/lib/compiler/implementation/scanner/listener.dart b/dart/lib/compiler/implementation/scanner/listener.dart
index e8eca74491af35364fdc8c86670f68470f094ccf..1b549f898e7922fed8a4ff5ae75149c1b1c325a2 100644
--- a/dart/lib/compiler/implementation/scanner/listener.dart
+++ b/dart/lib/compiler/implementation/scanner/listener.dart
@@ -493,6 +493,11 @@ class Listener {
     return skipToEof(token);
   }
 
+  Token unmatched(Token token) {
+    error("unmatched '${token.slowToString()}'", token);
+    return skipToEof(token);
+  }
+
   skipToEof(Token token) {
     while (token.info !== EOF_INFO) {
       token = token.next;
@@ -826,6 +831,11 @@ class ElementListener extends Listener {
     }
   }
 
+  Token unmatched(Token token) {
+    listener.cancel("unmatched '${token.slowToString()}'", token: token);
+    return skipToEof(token);
+  }
+
   void recoverableError(String message, [Token token, Node node]) {
     listener.cancel(message, token: token, node: node);
   }