Infer types of catpured variables and use the types in the SSA builder.

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

Index: sdk/lib/_internal/compiler/implementation/types/types.dart
===================================================================
--- sdk/lib/_internal/compiler/implementation/types/types.dart	(revision 19427)
+++ sdk/lib/_internal/compiler/implementation/types/types.dart	(working copy)
@@ -25,6 +25,7 @@
  */
 abstract class TypesInferrer {
   analyzeMain(Element element);
+  getConcreteReturnTypeOfElement(Element element);
   getConcreteTypeOfElement(Element element);
   getConcreteTypeOfNode(Element owner, Node node);
 }
@@ -79,8 +80,8 @@
   ConcreteType getGuaranteedTypeOfElement(Element element) {
     return measure(() {
       if (typesInferrer != null) {
-        ConcreteType guaranteedType = typesInferrer
-            .getConcreteTypeOfElement(element);
+        ConcreteType guaranteedType =
+            typesInferrer .getConcreteTypeOfElement(element);
         if (guaranteedType != null) return guaranteedType;
       }
       if (!element.isParameter()) return null;
@@ -103,6 +104,17 @@
     });
   }
 
+  ConcreteType getGuaranteedReturnTypeOfElement(Element element) {
+    return measure(() {
+      if (typesInferrer != null) {
+        ConcreteType guaranteedType =
+            typesInferrer.getConcreteReturnTypeOfElement(element);
+        if (guaranteedType != null) return guaranteedType;
+      }
+      return null;
+    });
+  }
+
   /**
    * Return the (inferred) guaranteed concrete type of [node] or null.
    * [node] must be an AST node of [owner].