Refine the type of a local after it has been used as the receiver of a call.

sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart

Index: sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart	(revision 26339)
+++ sdk/lib/_internal/compiler/implementation/types/inferrer_visitor.dart	(working copy)
@@ -79,6 +79,12 @@
    * Adds [newType] as an input of [phiType].
    */
   T addPhiInput(Element element, T phiType, T newType);
+
+  /**
+   * Returns a new receiver type for this [selector] applied to
+   * [receiverType].
+   */
+  T refineReceiver(Selector selector, T receiverType);
 }
 
 /**