Refactor and simplify the dart2dart renamer.

sdk/lib/_internal/compiler/implementation/resolution/members.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 resolution;
 
 abstract class TreeElements {
   AnalyzableElement get analyzedElement;
   Iterable<Node> get superUses;
 
@@ skipping 728 matching lines @@
   }
 
   TreeElements resolveField(FieldElementX element) {
     VariableDefinitions tree = element.parseNode(compiler);
     if(element.modifiers.isStatic && element.isTopLevel) {
       error(element.modifiers.getStatic(),
             MessageKind.TOP_LEVEL_VARIABLE_DECLARED_STATIC);
     }
     ResolverVisitor visitor = visitorFor(element);
     ResolutionRegistry registry = visitor.registry;
+    // TODO(johnniwinther): Maybe remove this when placeholderCollector migrates
+    // to the backend ast.
+    registry.defineElement(tree.definitions.nodes.head, element);
     // TODO(johnniwinther): Share the resolved type between all variables
     // declared in the same declaration.
     if (tree.type != null) {
       element.variables.type = visitor.resolveTypeAnnotation(tree.type);
     } else {
       element.variables.type = const DynamicType();
     }
 
     Expression initializer = element.initializer;
     Modifiers modifiers = element.modifiers;
@@ skipping 4181 matching lines @@
 }
 
 /// The result for the resolution of the `assert` method.
 class AssertResult implements ResolutionResult {
   const AssertResult();
 
   Element get element => null;
 
   String toString() => 'AssertResult()';
 }