Add support for attribute serialization.

compiler/backend/src/org/jetbrains/kotlin/codegen/ImplementationBodyCodegen.java

@@ -128,7 +128,7 @@ public class ImplementationBodyCodegen extends ClassBodyCodegen {
                 descriptor, extension,
                 parentCodegen instanceof ImplementationBodyCodegen
                 ? ((ImplementationBodyCodegen) parentCodegen).serializer
-                : DescriptorSerializer.createTopLevel(extension),
+                : DescriptorSerializer.createTopLevel(extension, null),
                 state.getProject()
         );
 

compiler/backend/src/org/jetbrains/kotlin/codegen/PackagePartCodegen.java

@@ -127,7 +127,7 @@ public class PackagePartCodegen extends MemberCodegen<KtFile> {
         List<MemberDescriptor> members = CodegenUtil.getMemberDescriptorsToGenerate(codegen.element, codegen.bindingContext);
 
         JvmSerializerExtension extension = new JvmSerializerExtension(codegen.v.getSerializationBindings(), codegen.state);
-        DescriptorSerializer serializer = DescriptorSerializer.createTopLevel(extension);
+        DescriptorSerializer serializer = DescriptorSerializer.createTopLevel(extension, null);
         ProtoBuf.Package.Builder builder = serializer.packagePartProto(codegen.element.getPackageFqName(), members);
         extension.serializeJvmPackage(builder, packagePartType);