Do not use the namer for naming closure elements.

pkg/compiler/lib/src/compiler.dart

Index: pkg/compiler/lib/src/compiler.dart
diff --git a/pkg/compiler/lib/src/compiler.dart b/pkg/compiler/lib/src/compiler.dart
index c26087dc10523cce49a3b4959a4d68b82c995ee3..4c3a774a17abde9c61d05582001fcfc5bf85f53b 100644
--- a/pkg/compiler/lib/src/compiler.dart
+++ b/pkg/compiler/lib/src/compiler.dart
@@ -1049,14 +1049,11 @@ abstract class Compiler implements DiagnosticListener {
     globalDependencies =
         new CodegenRegistry(this, new TreeElementMapping(null));
 
-    closureMapping.ClosureNamer closureNamer;
     if (emitJavaScript) {
       js_backend.JavaScriptBackend jsBackend =
           new js_backend.JavaScriptBackend(this, generateSourceMap);
-      closureNamer = jsBackend.namer;
       backend = jsBackend;
     } else {
-      closureNamer = new closureMapping.ClosureNamer();
       backend = new dart_backend.DartBackend(this, strips,
                                              multiFile: dart2dartMultiFile);
       if (dumpInfo) {
@@ -1071,7 +1068,7 @@ abstract class Compiler implements DiagnosticListener {
       parser = new ParserTask(this),
       patchParser = new PatchParserTask(this),
       resolver = new ResolverTask(this, backend.constantCompilerTask),
-      closureToClassMapper = new closureMapping.ClosureTask(this, closureNamer),
+      closureToClassMapper = new closureMapping.ClosureTask(this),
       checker = new TypeCheckerTask(this),
       irBuilder = new IrBuilderTask(this),
       typesTask = new ti.TypesTask(this),