Split World usage into open, inference, and closed world.

pkg/compiler/lib/src/closure.dart

Index: pkg/compiler/lib/src/closure.dart
diff --git a/pkg/compiler/lib/src/closure.dart b/pkg/compiler/lib/src/closure.dart
index 7b71e69294b9becbd635f0f92b7d426f8c000ad5..547d36fedb18d174a61e0201283c0c949e524cae 100644
--- a/pkg/compiler/lib/src/closure.dart
+++ b/pkg/compiler/lib/src/closure.dart
@@ -1054,8 +1054,7 @@ class ClosureTranslator extends Visitor {
     ClosureClassElement globalizedElement =
         new ClosureClassElement(node, closureName, compiler, element);
     // Extend [globalizedElement] as an instantiated class in the closed world.
-    compiler.world
-        .registerClass(globalizedElement, isDirectlyInstantiated: true);
+    compiler.inferenceWorld.registerClosureClass(globalizedElement);
     FunctionElement callElement = new SynthesizedCallMethodElementX(
         Identifiers.call, element, globalizedElement, node, elements);
     backend.maybeMarkClosureAsNeededForReflection(