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

pkg/front_end/lib/src/fasta/kernel/kernel_library_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_library_builder;
 
 import 'package:kernel/ast.dart';
 
 import 'package:kernel/clone.dart' show CloneVisitor;
 
@@ skipping 96 matching lines @@
     KernelTypeBuilder type = new KernelMixinApplicationBuilder(
         supertype, mixins, this, charOffset, fileUri);
     return addType(type);
   }
 
   KernelTypeBuilder addVoidType(int charOffset) {
     return addNamedType("void", null, charOffset);
   }
 
   void addClass(
+      String documentationComment,
       List<MetadataBuilder> metadata,
       int modifiers,
       String className,
       List<TypeVariableBuilder> typeVariables,
       KernelTypeBuilder supertype,
       List<KernelTypeBuilder> interfaces,
       int charOffset) {
     // Nested declaration began in `OutlineBuilder.beginClassDeclaration`.
     var declaration = endNestedDeclaration(className)
       ..resolveTypes(typeVariables, this);
     assert(declaration.parent == libraryDeclaration);
     Map<String, MemberBuilder> members = declaration.members;
     Map<String, MemberBuilder> constructors = declaration.constructors;
     Map<String, MemberBuilder> setters = declaration.setters;
 
     Scope classScope = new Scope(
         members, setters, scope.withTypeVariables(typeVariables),
         isModifiable: false);
 
     // When looking up a constructor, we don't consider type variables or the
     // library scope.
     Scope constructorScope =
         new Scope(constructors, null, null, isModifiable: false);
     ClassBuilder cls = new SourceClassBuilder(
+        documentationComment,
         metadata,
         modifiers,
         className,
         typeVariables,
         applyMixins(supertype,
             subclassName: className, typeVariables: typeVariables),
         interfaces,
         classScope,
         constructorScope,
         this,
@@ skipping 55 matching lines @@
                 messageTypeVariableSameNameAsEnclosing, tv.charOffset, fileUri);
           }
         }
       }
     }
     return typeVariablesByName;
   }
 
   KernelTypeBuilder applyMixin(
       KernelTypeBuilder supertype, KernelTypeBuilder mixin, String signature,
-      {List<MetadataBuilder> metadata,
+      {String documentationComment,
+      List<MetadataBuilder> metadata,
       String name,
       List<TypeVariableBuilder> typeVariables,
       int modifiers: abstractMask,
       List<KernelTypeBuilder> interfaces,
       int charOffset: -1}) {
     var constructors = <String, MemberBuilder>{};
     bool isNamed = name != null;
     SourceClassBuilder builder;
     if (isNamed) {
       modifiers |= namedMixinApplicationMask;
     } else {
       name = supertype.name;
       int index = name.indexOf("^");
       if (index != -1) {
         name = name.substring(0, index);
       }
       name = "$name&${mixin.name}$signature";
       builder = mixinApplicationClasses[name];
     }
     if (builder == null) {
       builder = new SourceClassBuilder(
+          documentationComment,
           metadata,
           modifiers,
           name,
           typeVariables,
           supertype,
           interfaces,
           new Scope(<String, MemberBuilder>{}, <String, MemberBuilder>{},
               scope.withTypeVariables(typeVariables),
               isModifiable: false),
           new Scope(constructors, null, null, isModifiable: false),
@@ skipping 618 matching lines @@
           mixinApplicationClasses.putIfAbsent(name, () => builder);
       if (existing != builder) {
         part.scope.local.remove(name);
       }
     });
     super.includePart(part);
     nativeMethods.addAll(part.nativeMethods);
     boundlessTypeVariables.addAll(part.boundlessTypeVariables);
   }
 }