Fix for summarizing triple slash documentation comments.

pkg/analyzer/test/src/summary/resynthesize_common.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 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/standard_resolution_map.dart';
 import 'package:analyzer/dart/constant/value.dart';
 import 'package:analyzer/dart/element/element.dart';
@@ skipping 1464 matching lines @@
 
   test_class_documented() {
     checkLibrary('''
 // Extra comment so doc comment offset != 0
 /**
  * Docs
  */
 class C {}''');
   }
 
+  test_class_documented_tripleSlash() {
+    checkLibrary('''
+/// aaa
+/// bbbb
+/// cc
+class C {}''');
+  }
+
   test_class_documented_with_references() {
     checkLibrary('''
 /**
  * Docs referring to [D] and [E]
  */
 class C {}
 
 class D {}
 class E {}''');
   }
@@ skipping 3345 matching lines @@
       fail('Unexpectedly tried to get unlinked summary for $uri');
     }
     return serializedUnit;
   }
 
   @override
   bool hasLibrarySummary(String uri) {
     return true;
   }
 }