dart2dart: Implementation of simple try/catch.

pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart

Index: pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
diff --git a/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart b/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
index c4611570fd63e18dd7b68df0f8b813549b3ac33b..61e211c093ab1ffc1d714a531beba88641440c21 100644
--- a/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
+++ b/pkg/compiler/lib/src/tree_ir/optimization/loop_rewriter.dart
@@ -118,6 +118,12 @@ class LoopRewriter extends RecursiveVisitor with PassMixin {
     return node;
   }
 
+  Statement visitTryStatement(TryStatement node) {
+    node.tryBody = visitStatement(node.tryBody);
+    node.catchBody = visitStatement(node.catchBody);
+    return node;
+  }
+
   Statement visitFunctionDeclaration(FunctionDeclaration node) {
     new LoopRewriter().rewrite(node.definition);
     node.next = visitStatement(node.next);