Tests for `void`.

pkg/compiler/lib/src/js_backend/backend.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 js_backend.backend;
 
 import 'dart:async' show Future;
 
 import 'package:js_runtime/shared/embedded_names.dart' as embeddedNames;
 
@@ skipping 1155 matching lines @@
         rti.registerRtiDependency(helpers.mapLiteralClass, cls);
       } else if (cls == helpers.boundClosureClass) {
         impactTransformer.registerBackendImpact(
             impactBuilder, impacts.boundClosureClass);
       } else if (isNativeOrExtendsNative(cls)) {
         impactTransformer.registerBackendImpact(
             impactBuilder, impacts.nativeOrExtendsClass);
       } else if (cls == helpers.mapLiteralClass) {
         impactTransformer.registerBackendImpact(
             impactBuilder, impacts.mapLiteralClass);
+      } else if (cls == commonElements.objectClass) {
+        impactTransformer.registerBackendImpact(
+            impactBuilder, impacts.objectClass);
       }
     }
     if (cls == helpers.closureClass) {
       impactTransformer.registerBackendImpact(
           impactBuilder, impacts.closureClass);
     }
     if (cls == commonElements.stringClass || cls == helpers.jsStringClass) {
       addInterceptors(helpers.jsStringClass, impactBuilder,
           forResolution: forResolution);
     } else if (cls == commonElements.listClass ||
@@ skipping 2042 matching lines @@
       resolution.emptyCache();
     }
   }
 }
 
 class JavaScriptBackendClasses implements BackendClasses {
   final BackendHelpers helpers;
 
   JavaScriptBackendClasses(this.helpers);
 
+  ClassElement get voidClass => helpers.voidClass;
   ClassElement get intClass => helpers.jsIntClass;
   ClassElement get uint32Class => helpers.jsUInt32Class;
   ClassElement get uint31Class => helpers.jsUInt31Class;
   ClassElement get positiveIntClass => helpers.jsPositiveIntClass;
   ClassElement get doubleClass => helpers.jsDoubleClass;
   ClassElement get numClass => helpers.jsNumberClass;
   ClassElement get stringClass => helpers.jsStringClass;
   ClassElement get listClass => helpers.jsArrayClass;
   ClassElement get mutableListClass => helpers.jsMutableArrayClass;
   ClassElement get constListClass => helpers.jsUnmodifiableArrayClass;
@@ skipping 33 matching lines @@
   @override
   bool isNativeClass(ClassElement element) {
     return helpers.backend.isNative(element);
   }
 
   @override
   bool isNativeMember(MemberElement element) {
     return helpers.backend.isNative(element);
   }
 }