Use entities in class_stub_generator.

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

 // Copyright (c) 2012, 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.
 
 library dart2js.js_emitter.code_emitter_task;
 
 import 'package:js_runtime/shared/embedded_names.dart' show JsBuiltin;
 
 import '../common.dart';
 import '../common/tasks.dart' show CompilerTask;
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart';
 import '../elements/elements.dart'
     show
-    ClassElement,
-    Entity,
-    FieldElement,
-    FunctionElement,
-    MethodElement,
-    TypeVariableElement;
+        ClassElement,
+        Entity,
+        FieldElement,
+        FunctionElement,
+        MethodElement,
+        TypeVariableElement;
 import '../js/js.dart' as jsAst;
-import '../js_backend/js_backend.dart'
-    show
-    JavaScriptBackend,
-    Namer;
+import '../js_backend/js_backend.dart' show JavaScriptBackend, Namer;
 import '../world.dart' show ClosedWorld;
 import 'full_emitter/emitter.dart' as full_js_emitter;
 import 'lazy_emitter/emitter.dart' as lazy_js_emitter;
 import 'program_builder/program_builder.dart';
 import 'startup_emitter/emitter.dart' as startup_js_emitter;
 
 import 'metadata_collector.dart' show MetadataCollector;
 import 'native_emitter.dart' show NativeEmitter;
 import 'type_test_registry.dart' show TypeTestRegistry;
 
@@ skipping 216 matching lines @@
   bool isConstantInlinedOrAlreadyEmitted(ConstantValue constant);
 
   /// Returns the JS code for accessing the given [constant].
   jsAst.Expression constantReference(ConstantValue constant);
 
   /// Returns the JS template for the given [builtin].
   jsAst.Template templateForBuiltin(JsBuiltin builtin);
 
   void invalidateCaches();
 }