Move towards using WorldImpact for codegen

pkg/compiler/lib/src/common/backend_api.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.backend_api;
 
 import 'dart:async' show Future;
 
 import '../common.dart';
 import '../common/codegen.dart' show CodegenImpact;
@@ skipping 12 matching lines @@
 import '../io/source_information.dart' show SourceInformationStrategy;
 import '../js_backend/backend_helpers.dart' as js_backend show BackendHelpers;
 import '../js_backend/js_backend.dart' as js_backend;
 import '../library_loader.dart' show LibraryLoader, LoadedLibraries;
 import '../native/native.dart' as native show NativeEnqueuer, maybeEnableNative;
 import '../patch_parser.dart'
     show checkNativeAnnotation, checkJsInteropAnnotation;
 import '../serialization/serialization.dart'
     show DeserializerPlugin, SerializerPlugin;
 import '../tree/tree.dart' show Node;
-import '../universe/world_impact.dart' show ImpactStrategy, WorldImpact;
+import '../universe/world_impact.dart'
+    show ImpactStrategy, WorldImpact, WorldImpactBuilder;
 import 'codegen.dart' show CodegenWorkItem;
 import 'registry.dart' show Registry;
 import 'tasks.dart' show CompilerTask;
 
 abstract class Backend extends Target {
   final Compiler compiler;
 
   Backend(this.compiler);
 
   /// Returns true if the backend supports reflection.
@@ skipping 65 matching lines @@
 
   /// Enable compilation of code with compile time errors. Returns `true` if
   /// supported by the backend.
   bool enableCodegenWithErrorsIfSupported(Spannable node);
 
   /// Enable deferred loading. Returns `true` if the backend supports deferred
   /// loading.
   bool enableDeferredLoadingIfSupported(Spannable node, Registry registry);
 
   /// Called during codegen when [constant] has been used.
-  void registerCompileTimeConstant(ConstantValue constant, Registry registry) {}
+  void computeImpactForCompileTimeConstant(ConstantValue constant,
+      WorldImpactBuilder impactBuilder, bool isForResolution) {}
 
   /// Called to notify to the backend that a class is being instantiated.
   // TODO(johnniwinther): Remove this. It's only called once for each [cls] and
   // only with [Compiler.globalDependencies] as [registry].
   void registerInstantiatedClass(
       ClassElement cls, Enqueuer enqueuer, Registry registry) {}
 
   /// Called to notify to the backend that a class is implemented by an
   /// instantiated class.
   void registerImplementedClass(
@@ skipping 272 matching lines @@
   }
 }
 
 /// Interface for serialization of backend specific data.
 class BackendSerialization {
   const BackendSerialization();
 
   SerializerPlugin get serializer => const SerializerPlugin();
   DeserializerPlugin get deserializer => const DeserializerPlugin();
 }