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

pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart

Index: pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart
diff --git a/pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart b/pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart
index 143330b6eddda4c00bca9639a770b00720e600c3..1bce990241a61b97bfc944e19630fefc6243730c 100644
--- a/pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart
+++ b/pkg/front_end/lib/src/fasta/kernel/kernel_enum_builder.dart
@@ -74,6 +74,7 @@ class KernelEnumBuilder extends SourceClassBuilder
   final KernelNamedTypeBuilder listType;
 
   KernelEnumBuilder.internal(
+      String documentationComment,
       List<MetadataBuilder> metadata,
       String name,
       Scope scope,
@@ -87,8 +88,8 @@ class KernelEnumBuilder extends SourceClassBuilder
       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,
@@ -186,6 +187,7 @@ class KernelEnumBuilder extends SourceClassBuilder
     }
     MapLiteral toStringMap = new MapLiteral(toStringEntries, isConst: true);
     KernelEnumBuilder enumBuilder = new KernelEnumBuilder.internal(
+        null,
         metadata,
         name,
         new Scope(members, null, parent.scope, isModifiable: false),