Add summary support for ParameterElement.defaultValueCode.

pkg/analyzer/test/src/summary/resynthesize_test.dart

 // Copyright (c) 2015, 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 test.src.serialization.elements_test;
 
 import 'dart:convert';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 786 matching lines @@
     if (resynthesized is FieldFormalParameterElementImpl &&
         original is FieldFormalParameterElementImpl) {
       if (original.field == null) {
         expect(resynthesized.field, isNull, reason: '$desc field');
       } else {
         expect(resynthesized.field, isNotNull, reason: '$desc field');
         compareFieldElements(
             resynthesized.field, original.field, '$desc field');
       }
     }
+    expect(resynthesized.defaultValueCode, original.defaultValueCode,
+        reason: desc);
   }
 
   void comparePrefixElements(PrefixElementImpl resynthesized,
       PrefixElementImpl original, String desc) {
     compareElements(resynthesized, original, desc);
   }
 
   void comparePropertyAccessorElements(
       PropertyAccessorElementImpl resynthesized,
       PropertyAccessorElementImpl original,
@@ skipping 3096 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }