Move most codegen registrations into WorldImpact.

pkg/compiler/lib/src/js_backend/backend_impact.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.
 
 library dart2js.js_helpers.impact;
 
 import '../common/names.dart' show
     Identifiers;
 import '../compiler.dart' show
     Compiler;
@@ skipping 256 matching lines @@
       staticUses: [
         helpers.checkSubtype,
         // TODO(johnniwinther): Investigate why this is needed.
         helpers.setRuntimeTypeInfo,
         helpers.getRuntimeTypeInfo],
       instantiatedClasses: [
         coreClasses.listClass],
       otherImpacts: [
         getRuntimeTypeArgument]);
 
+  BackendImpact get genericIsCheck => new BackendImpact(
+      instantiatedClasses: [
+        coreClasses.listClass]);
+
   BackendImpact get genericCheckedModeTypeCheck => new BackendImpact(
       staticUses: [
         helpers.assertSubtype]);
 
   BackendImpact get typeVariableTypeCheck => new BackendImpact(
       staticUses: [
         helpers.checkSubtypeOfRuntimeType]);
 
   BackendImpact get typeVariableCheckedModeTypeCheck => new BackendImpact(
       staticUses: [
         helpers.assertSubtypeOfRuntimeType]);
 
   BackendImpact get functionTypeCheck => new BackendImpact(
       staticUses: [
         helpers.functionTypeTestMetaHelper]);
 
   BackendImpact get nativeTypeCheck => new BackendImpact(
       staticUses: [
         // We will neeed to add the "$is" and "$as" properties on the
         // JavaScript object prototype, so we make sure
         // [:defineProperty:] is compiled.
         helpers.defineProperty]);
 
   BackendImpact get closure => new BackendImpact(
       instantiatedClasses: [
         coreClasses.functionClass]);
 }