Expand ResolvedAst to handle synthetic constructors.

pkg/compiler/lib/src/common/codegen.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.common.codegen;
 
 import '../common.dart';
 import '../compiler.dart' show Compiler;
 import '../constants/values.dart' show ConstantValue;
 import '../dart_types.dart' show DartType, InterfaceType;
 import '../elements/elements.dart'
     show
         AstElement,
         ClassElement,
         Element,
         FunctionElement,
-        LocalFunctionElement;
+        LocalFunctionElement,
+        ResolvedAst;
 import '../enqueue.dart' show CodegenEnqueuer;
-import '../resolution/tree_elements.dart' show TreeElements;
 import '../universe/use.dart' show DynamicUse, StaticUse, TypeUse;
 import '../universe/world_impact.dart'
     show WorldImpact, WorldImpactBuilder, WorldImpactVisitor;
 import '../util/util.dart' show Pair, Setlet;
 import 'registry.dart' show Registry, EagerRegistry;
 import 'work.dart' show ItemCompilationContext, WorkItem;
 
 class CodegenImpact extends WorldImpact {
   const CodegenImpact();
 
@@ skipping 198 matching lines @@
 
   factory CodegenWorkItem(Compiler compiler, AstElement element,
       ItemCompilationContext compilationContext) {
     // If this assertion fails, the resolution callbacks of the backend may be
     // missing call of form registry.registerXXX. Alternatively, the code
     // generation could spuriously be adding dependencies on things we know we
     // don't need.
     assert(invariant(
         element, compiler.enqueuer.resolution.hasBeenProcessed(element),
         message: "$element has not been resolved."));
-    assert(invariant(element, element.resolvedAst.elements != null,
+    assert(invariant(element, element.hasResolvedAst,
         message: 'Resolution tree is null for $element in codegen work item'));
     return new CodegenWorkItem.internal(element, compilationContext);
   }
 
   CodegenWorkItem.internal(
       AstElement element, ItemCompilationContext compilationContext)
       : super(element, compilationContext);
 
-  TreeElements get resolutionTree => element.resolvedAst.elements;
+  ResolvedAst get resolvedAst => element.resolvedAst;
 
   WorldImpact run(Compiler compiler, CodegenEnqueuer world) {
     if (world.isProcessed(element)) return const WorldImpact();
 
     registry = new CodegenRegistry(compiler, element);
     return compiler.codegen(this, world);
   }
 }