Introduce WorldImpact

pkg/compiler/lib/src/dart_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.
 
 part of dart_backend;
 
 // TODO(ahe): This class is simply wrong.  This backend should use
 // elements when it can, not AST nodes.  Perhaps a [Map<Element,
 // TreeElements>] is what is needed.
 class ElementAst {
@@ skipping 111 matching lines @@
       classElement.ensureResolved(compiler);
     }
     // Enqueue the methods that the VM might invoke on user objects because
     // we don't trust the resolution to always get these included.
     world.registerInvocation(new Selector.call("toString", null, 0));
     world.registerInvokedGetter(new Selector.getter("hashCode", null));
     world.registerInvocation(new Selector.binaryOperator("=="));
     world.registerInvocation(new Selector.call("compareTo", null, 1));
   }
 
-  void codegen(CodegenWorkItem work) { }
+  WorldImpact codegen(CodegenWorkItem work) => const WorldImpact();
+
   /**
    * Tells whether we should output given element. Corelib classes like
    * Object should not be in the resulting code.
    */
   @override
   bool shouldOutput(Element element) {
     return (!element.library.isPlatformLibrary &&
             !element.isSynthesized &&
             element is! AbstractFieldElement)
         || mirrorRenamer.isMirrorHelperLibrary(element.library);
@@ skipping 330 matching lines @@
 class _ElementAstCreationContext implements ElementAstCreationContext {
   final Compiler compiler;
   final ConstantSystem constantSystem;
 
   _ElementAstCreationContext(this.compiler, this.constantSystem);
 
   DartTypes get dartTypes => compiler.types;
 
   InternalErrorFunction get internalError => compiler.internalError;
 }