Prototype re-compiling methods in dart2js

lib/compiler/implementation/universe.dart

Index: lib/compiler/implementation/universe.dart
diff --git a/lib/compiler/implementation/universe.dart b/lib/compiler/implementation/universe.dart
index 8cdf683360c97470d81d24a06a4cf8adef55b659..27e3546c5c20983fe243a3912b0c9b60fea88026 100644
--- a/lib/compiler/implementation/universe.dart
+++ b/lib/compiler/implementation/universe.dart
@@ -11,6 +11,7 @@ class Universe {
   final Map<SourceString, Set<Selector>> invokedNames;
   final Map<SourceString, Set<Selector>> invokedGetters;
   final Map<SourceString, Set<Selector>> invokedSetters;
+  final Map<SourceString, ClassElement> invokedFieldSetters;
   // TODO(ngeoffray): This should be a Set<Type>.
   final Set<Element> isChecks;
   final RuntimeTypeInformation rti;
@@ -23,6 +24,7 @@ class Universe {
                invokedNames = new Map<SourceString, Set<Selector>>(),
                invokedGetters = new Map<SourceString, Set<Selector>>(),
                invokedSetters = new Map<SourceString, Set<Selector>>(),
+               invokedFieldSetters = new Map<SourceString, ClassElement>(),
                isChecks = new Set<Element>(),
                rti = new RuntimeTypeInformation();