Add documentationComment for Class to Kernel. Parse it. Resynthesize in Analyzer.

pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.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 fasta.kernel_enum_builder;
 
 import 'package:kernel/ast.dart'
     show
         Arguments,
         Class,
@@ skipping 56 matching lines @@
 
   final KernelNamedTypeBuilder intType;
 
   final KernelNamedTypeBuilder stringType;
 
   final KernelNamedTypeBuilder objectType;
 
   final KernelNamedTypeBuilder listType;
 
   KernelEnumBuilder.internal(
+      String documentationComment,
       List<MetadataBuilder> metadata,
       String name,
       Scope scope,
       Scope constructors,
       Class cls,
       this.constantNamesAndOffsets,
       this.toStringMap,
       this.intType,
       this.listType,
       this.objectType,
       this.stringType,
       LibraryBuilder parent,
       int charOffset)
-      : super(metadata, 0, name, null, null, null, scope, constructors, parent,
-            null, charOffset, cls);
+      : super(documentationComment, metadata, 0, name, null, null, null, scope,
+            constructors, parent, null, charOffset, cls);
 
   factory KernelEnumBuilder(
       List<MetadataBuilder> metadata,
       String name,
       List<Object> constantNamesAndOffsets,
       KernelLibraryBuilder parent,
       int charOffset,
       int charEndOffset) {
     constantNamesAndOffsets ??= const <Object>[];
     // TODO(ahe): These types shouldn't be looked up in scope, they come
@@ skipping 77 matching lines @@
       }
       KernelFieldBuilder fieldBuilder = new KernelFieldBuilder(null, selfType,
           name, constMask | staticMask, parent, charOffset, null, true);
       members[name] = fieldBuilder;
       toStringEntries.add(new MapEntry(
           new IntLiteral(index), new StringLiteral("$className.$name")));
       index++;
     }
     MapLiteral toStringMap = new MapLiteral(toStringEntries, isConst: true);
     KernelEnumBuilder enumBuilder = new KernelEnumBuilder.internal(
+        null,
         metadata,
         name,
         new Scope(members, null, parent.scope, isModifiable: false),
         new Scope(constructors, null, null, isModifiable: false),
         cls,
         constantNamesAndOffsets,
         toStringMap,
         intType,
         listType,
         objectType,
@@ skipping 87 matching lines @@
     }
     return super.build(libraryBuilder, coreLibrary);
   }
 
   @override
   Builder findConstructorOrFactory(
       String name, int charOffset, Uri uri, LibraryBuilder library) {
     return null;
   }
 }