Resynthesize _DeferredClassElement lazily.

pkg/analyzer/lib/src/dart/element/element.dart

 // Copyright (c) 2014, 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 analyzer.src.dart.element.element;
 
 import 'dart:collection';
 import 'dart:math' show min;
 
 import 'package:analyzer/dart/ast/ast.dart';
@@ skipping 903 matching lines @@
     return false;
   }
 
   /**
    * Return the [ClassElementImpl] of the given [classElement].  May throw an
    * exception if the [ClassElementImpl] cannot be provided (should not happen
    * though).
    */
   static ClassElementImpl getImpl(ClassElement classElement) {
     if (classElement is ClassElementHandle) {
+      classElement.ensureActualElementComplete();
       return getImpl(classElement.actualElement);
     }
     return classElement as ClassElementImpl;
   }
 }
 
 /**
  * A concrete implementation of a [CompilationUnitElement].
  */
 class CompilationUnitElementImpl extends UriReferencedElementImpl
@@ skipping 4103 matching lines @@
 
   @override
   void visitElement(Element element) {
     int offset = element.nameOffset;
     if (offset != -1) {
       map[offset] = element;
     }
     super.visitElement(element);
   }
 }