Move codegen registration to transformImpact method.

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;
+import '../common/resolution.dart' show
+    ResolutionImpact;
 import '../compiler.dart' show
     Compiler;
 import '../compile_time_constants.dart' show
     BackendConstantEnvironment,
     ConstantCompilerTask;
 import '../constants/expressions.dart' show
     ConstantExpression;
 import '../constants/constant_system.dart' show
     ConstantSystem;
 import '../constants/values.dart' show
@@ skipping 33 matching lines @@
     Send;
 import '../universe/call_structure.dart' show
     CallStructure;
 import '../universe/world_impact.dart' show
     WorldImpact;
 
 import 'codegen.dart' show
     CodegenWorkItem;
 import 'registry.dart' show
     Registry;
-import 'resolution.dart' show
-    ResolutionCallbacks;
 import 'tasks.dart' show
     CompilerTask;
 import 'work.dart' show
     ItemCompilationContext;
 
 
 abstract class Backend {
   final Compiler compiler;
 
   Backend(this.compiler);
 
   /// Returns true if the backend supports reflection.
   bool get supportsReflection;
 
   /// The [ConstantSystem] used to interpret compile-time constants for this
   /// backend.
   ConstantSystem get constantSystem;
 
   /// The constant environment for the backend interpretation of compile-time
   /// constants.
   BackendConstantEnvironment get constants;
 
   /// The compiler task responsible for the compilation of constants for both
   /// the frontend and the backend.
   ConstantCompilerTask get constantCompilerTask;
 
-  /// Backend callback methods for the resolution phase.
-  ResolutionCallbacks get resolutionCallbacks;
+  /// Backend transformation methods for the world impacts.
+  ImpactTransformer get impactTransformer;
 
   /// The strategy used for collecting and emitting source information.
   SourceInformationStrategy get sourceInformationStrategy {
     return const SourceInformationStrategy();
   }
 
   // TODO(johnniwinther): Move this to the JavaScriptBackend.
   String get patchVersion => null;
 
   /// Set of classes that need to be considered for reflection although not
   /// otherwise visible during resolution.
   Iterable<ClassElement> classesRequiredForReflection = const [];
 
   // Given a [FunctionElement], return a buffer with the code generated for it
   // or null if no code was generated.
   CodeBuffer codeOf(Element element) => null;
 
   void initializeHelperClasses() {}
 
   void enqueueHelpers(ResolutionEnqueuer world, Registry registry);
+
   WorldImpact codegen(CodegenWorkItem work);
 
   // The backend determines the native resolution enqueuer, with a no-op
   // default, so tools like dart2dart can ignore the native classes.
   native.NativeEnqueuer nativeResolutionEnqueuer(world) {
     return new native.NativeEnqueuer();
   }
   native.NativeEnqueuer nativeCodegenEnqueuer(world) {
     return new native.NativeEnqueuer();
   }
@@ skipping 294 matching lines @@
   /// Returns the constant expression of [node], or `null` if [node] is not
   /// a constant expression.
   ConstantExpression getConstant(Node node);
 
   /// Registers [type] as instantiated.
   void registerInstantiatedType(InterfaceType type);
 
   /// Resolves [typeName] to a type in the context of [node].
   DartType resolveTypeFromString(Node node, String typeName);
 }
+
+/// Backend transformation methods for the world impacts.
+class ImpactTransformer {
+  /// Transform the [ResolutionImpact] into a [WorldImpact] adding the
+  /// backend dependencies for features used in [worldImpact].
+  WorldImpact transformResolutionImpact(ResolutionImpact worldImpact) {
+    return worldImpact;
+  }
+
+  /// Transform the [CodegenImpact] into a [WorldImpact] adding the
+  /// backend dependencies for features used in [worldImpact].
+  WorldImpact transformCodegenImpact(CodegenImpact worldImpact) {
+    return worldImpact;
+  }
+}