Prepare for decoupling analyzer ASTs from element model.

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

Index: pkg/analyzer/lib/dart/element/element.dart
diff --git a/pkg/analyzer/lib/dart/element/element.dart b/pkg/analyzer/lib/dart/element/element.dart
index cee76da7f31ea3d7578b26af66fdc9b29df5621f..12f08fcbcbd0ba407af6f84fba01cfdde1361c51 100644
--- a/pkg/analyzer/lib/dart/element/element.dart
+++ b/pkg/analyzer/lib/dart/element/element.dart
@@ -37,6 +37,7 @@
 library analyzer.dart.element.element;
 
 import 'package:analyzer/dart/ast/ast.dart';
+import 'package:analyzer/dart/ast/resolution_base_classes.dart';
 import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/type.dart';
 import 'package:analyzer/src/generated/engine.dart' show AnalysisContext;
@@ -563,7 +564,7 @@ abstract class ConstructorElement
  *
  * Clients may not extend, implement or mix-in this class.
  */
-abstract class Element implements AnalysisTarget {
+abstract class Element implements AnalysisTarget, ResolutionTarget {
   /**
    * A comparator that can be used to sort elements by their name offset.
    * Elements with a smaller offset will be sorted to be before elements with a
@@ -787,7 +788,8 @@ abstract class Element implements AnalysisTarget {
  *
  * Clients may not extend, implement or mix-in this class.
  */
-abstract class ElementAnnotation implements ConstantEvaluationTarget {
+abstract class ElementAnnotation
+    implements ConstantEvaluationTarget, ResolutionTarget {
   /**
    * An empty list of annotations.
    */