Create Namer and Emitter on codegen start.

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

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart2js.js_emitter;
 
 class ParameterStubGenerator {
   static final Set<Selector> emptySelectorSet = new Set<Selector>();
 
   final Namer namer;
   final Compiler compiler;
   final JavaScriptBackend backend;
+  final ClosedWorld closedWorld;
 
-  ParameterStubGenerator(this.compiler, this.namer, this.backend);
+  ParameterStubGenerator(
+      this.compiler, this.namer, this.backend, this.closedWorld);
 
   Emitter get emitter => backend.emitter.emitter;
   CodeEmitterTask get emitterTask => backend.emitter;
   DiagnosticReporter get reporter => compiler.reporter;
 
   bool needsSuperGetter(FunctionElement element) =>
       compiler.codegenWorld.methodsNeedingSuperGetter.contains(element);
 
   /**
    * Generates stubs to handle invocation of methods with optional
@@ skipping 235 matching lines @@
         }
       }
     }
 
     // Now run through the actual member selectors (eg. `foo$2(x, y)` and not
     // `call$2(x, y)`. Some of them have already been generated because of the
     // call-selectors (and they are in the renamedCallSelectors set.
     for (Selector selector in selectors.keys) {
       if (renamedCallSelectors.contains(selector)) continue;
       if (!selector.appliesUnnamed(member)) continue;
-      if (!selectors[selector]
-          .applies(member, selector, compiler.closedWorld)) {
+      if (!selectors[selector].applies(member, selector, closedWorld)) {
         continue;
       }
 
       if (untypedSelectors.add(selector)) {
         ParameterStubMethod stub =
             generateParameterStub(member, selector, null);
         if (stub != null) {
           stubs.add(stub);
         }
       }
     }
 
     return stubs;
   }
 }