Enforce LinkedReference.dependency == 0 for contained entities.

pkg/analyzer/test/src/summary/summarize_elements_test.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 analyzer.test.src.summary.summarize_elements_test;
 
 import 'package:analyzer/dart/element/element.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:analyzer/src/generated/source.dart';
 import 'package:analyzer/src/generated/source_io.dart';
@@ skipping 75 matching lines @@
    * Serialize the given [library] element, then deserialize it and store the
    * resulting summary in [linked] and [unlinkedUnits].
    */
   void serializeLibraryElement(LibraryElement library) {
     summarize_elements.LibrarySerializationResult serializedLib =
         summarize_elements.serializeLibrary(
             library, typeProvider, analysisContext.analysisOptions.strongMode);
     {
       List<int> buffer = serializedLib.linked.toBuffer();
       linked = new LinkedLibrary.fromBuffer(buffer);
+      validateLinkedLibrary(linked);
     }
     unlinkedUnits = serializedLib.unlinkedUnits.map((UnlinkedUnitBuilder b) {
       List<int> buffer = b.toBuffer();
       return new UnlinkedUnit.fromBuffer(buffer);
     }).toList();
     unitUris = serializedLib.unitUris;
   }
 
   @override
   void serializeLibraryText(String text, {bool allowErrors: false}) {
@@ skipping 41 matching lines @@
       } else {
         UnlinkedPublicNamespace namespace =
             computePublicNamespaceFromText(text, source);
         expect(canonicalize(namespace),
             canonicalize(unlinkedUnits[i].publicNamespace),
             reason: 'publicNamespace(${unitUris[i]})');
       }
     }
   }
 }