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 120401758a6766c0ddbb052955bc30fdd30dcff6..ca76d2bffbd80c325c29327f16905e77ee9d8b51 100644
--- a/pkg/compiler/lib/src/resolution/tree_elements.dart
+++ b/pkg/compiler/lib/src/resolution/tree_elements.dart
@@ -44,6 +44,7 @@ abstract class TreeElements {
   Iterable<Element> get otherDependencies;
 
   Element operator[](Node node);
+  Map<Node, DartType> get typesCache;
 
   SendStructure getSendStructure(Send send);
 
@@ -132,6 +133,7 @@ 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;