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

pkg/compiler/lib/src/js_emitter/class_stub_generator.dart

Index: pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
diff --git a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
index 447710dca781f2ef0320f282ad342a15fc5cd94f..31f79bf0ecdb38cf66c1731b74d27016899eefd3 100644
--- a/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
+++ b/pkg/compiler/lib/src/js_emitter/class_stub_generator.dart
@@ -83,8 +83,8 @@ class ClassStubGenerator {
     Set<Selector> generatedSelectors = new Set<Selector>();
     for (Selector selector in selectors.keys) {
       if (generatedSelectors.contains(selector)) continue;
-      if (!selector.appliesUnnamed(member, compiler.world)) continue;
-      if (selectors[selector].applies(member, selector, compiler.world)) {
+      if (!selector.appliesUnnamed(member, compiler.closedWorld)) continue;
+      if (selectors[selector].applies(member, selector, compiler.closedWorld)) {
         generatedSelectors.add(selector);
 
         jsAst.Name invocationName = namer.invocationName(selector);
@@ -125,7 +125,7 @@ class ClassStubGenerator {
         String ignore, Map<Selector, SelectorConstraints> selectors) {
       for (Selector selector in selectors.keys) {
         SelectorConstraints maskSet = selectors[selector];
-        if (maskSet.needsNoSuchMethodHandling(selector, compiler.world)) {
+        if (maskSet.needsNoSuchMethodHandling(selector, compiler.closedWorld)) {
           jsAst.Name jsName = namer.invocationMirrorInternalName(selector);
           jsNames[jsName] = selector;
         }