Add a public API for the results of constant evaluation

pkg/analyzer/lib/src/generated/element_handle.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 engine.element_handle;
 
-import 'ast.dart';
-import 'element.dart';
-import 'engine.dart';
-import 'java_core.dart';
-import 'java_engine.dart';
-import 'resolver.dart';
-import 'source.dart';
-import 'utilities_dart.dart';
+import 'package:analyzer/src/generated/ast.dart';
+import 'package:analyzer/src/generated/constant.dart';
+import 'package:analyzer/src/generated/element.dart';
+import 'package:analyzer/src/generated/engine.dart';
+import 'package:analyzer/src/generated/java_core.dart';
+import 'package:analyzer/src/generated/java_engine.dart';
+import 'package:analyzer/src/generated/resolver.dart';
+import 'package:analyzer/src/generated/source.dart';
+import 'package:analyzer/src/generated/utilities_dart.dart';
 
 /**
  * Instances of the class `ClassElementHandle` implement a handle to a `ClassElement`.
  */
 class ClassElementHandle extends ElementHandle implements ClassElement {
   /**
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
@@ skipping 1060 matching lines @@
    * Initialize a newly created element handle to represent the given element.
    *
    * @param element the element being represented
    */
   VariableElementHandle(VariableElement element) : super(element);
 
   @override
   VariableElement get actualElement => super.actualElement as VariableElement;
 
   @override
+  DartObject get constantValue => actualElement.constantValue;
+
+  @override
   bool get hasImplicitType => actualElement.hasImplicitType;
 
   @override
   FunctionElement get initializer => actualElement.initializer;
 
   @override
   bool get isConst => actualElement.isConst;
 
   @override
   bool get isFinal => actualElement.isFinal;
@@ skipping 14 matching lines @@
 }
 
 /**
  * TODO(scheglov) invalid implementation
  */
 class WeakReference<T> {
   final T value;
   WeakReference(this.value);
   T get() => value;
 }