Support for new catch syntax in dart2js

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 a6c8d782fc6b25030a5ae2f1e07fd673c6f15c77..cbbc89c441f1ae61c0229a1235f7846f1cdeb278 100644
--- a/dart/lib/compiler/implementation/scanner/listener.dart
+++ b/dart/lib/compiler/implementation/scanner/listener.dart
@@ -254,7 +254,7 @@ class Listener {
   void handleCaseMatch(Token caseKeyword, Token colon) {
   }
 
-  void handleCatchBlock(Token catchKeyword) {
+  void handleCatchBlock(Token onKeyword, Token catchKeyword) {
   }
 
   void handleFinallyBlock(Token finallyKeyword) {
@@ -1361,10 +1361,11 @@ class NodeListener extends ElementListener {
     pushNode(new CaseMatch(caseKeyword, popNode(), colon));
   }
 
-  void handleCatchBlock(Token catchKeyword) {
+  void handleCatchBlock(Token onKeyword, Token catchKeyword) {
     Block block = popNode();
     NodeList formals = popNode();
-    pushNode(new CatchBlock(formals, block, catchKeyword));
+    TypeAnnotation type = onKeyword != null ? popNode() : null;
+    pushNode(new CatchBlock(type, formals, block, type, catchKeyword));
   }
 
   void endSwitchStatement(Token switchKeyword, Token endToken) {