Add summary support for ShowElementCombinator.end and .offset.

pkg/analyzer/lib/src/summary/summarize_ast.dart

 // Copyright (c) 2016, 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 serialization.summarize_ast;
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
 import 'package:analyzer/dart/ast/visitor.dart';
 import 'package:analyzer/src/generated/utilities_dart.dart';
@@ skipping 391 matching lines @@
   }
 
   /**
    * Serialize a [Combinator] into an [UnlinkedCombinator].
    */
   UnlinkedCombinatorBuilder serializeCombinator(Combinator combinator) {
     UnlinkedCombinatorBuilder b = new UnlinkedCombinatorBuilder();
     if (combinator is ShowCombinator) {
       b.shows =
           combinator.shownNames.map((SimpleIdentifier id) => id.name).toList();
+      b.offset = combinator.offset;
+      b.end = combinator.end;
     } else if (combinator is HideCombinator) {
       b.hides =
           combinator.hiddenNames.map((SimpleIdentifier id) => id.name).toList();
     } else {
       throw new StateError(
           'Unexpected combinator type: ${combinator.runtimeType}');
     }
     return b;
   }
 
@@ skipping 703 matching lines @@
 /**
  * A [_TypeParameterScope] is a [_Scope] which defines [_ScopedTypeParameter]s.
  */
 class _TypeParameterScope extends _Scope {
   /**
    * Get the number of [_ScopedTypeParameter]s defined in this
    * [_TypeParameterScope].
    */
   int get length => _definedNames.length;
 }