dart2js send stats, includes:

pkg/compiler/lib/src/resolution/tree_elements.dart

Index: pkg/compiler/lib/src/resolution/tree_elements.dart
diff --git a/pkg/compiler/lib/src/resolution/tree_elements.dart b/pkg/compiler/lib/src/resolution/tree_elements.dart
index 993c3cc1ea78d268ca24d593eb33660fc7537d1a..44248937f0d49eebce353b434b07e075b97f32cb 100644
--- a/pkg/compiler/lib/src/resolution/tree_elements.dart
+++ b/pkg/compiler/lib/src/resolution/tree_elements.dart
@@ -17,6 +17,7 @@ abstract class TreeElements {
   Iterable<Element> get otherDependencies;
 
   Element operator[](Node node);
+  Map<Node, DartType> get typesCache;
 
   SendStructure getSendStructure(Send send);
 
@@ -100,6 +101,7 @@ class TreeElementMapping extends TreeElements {
   Map<Spannable, Selector> _selectors;
   Map<Spannable, TypeMask> _typeMasks;
   Map<Node, DartType> _types;
+  Map<Node, DartType> typesCache = <Node, DartType>{};
   Setlet<Node> _superUses;
   Setlet<Element> _otherDependencies;
   Map<Node, ConstantExpression> _constants;