Generate constants in server as we do in plugin

pkg/analysis_server/test/search/abstract_search_domain.dart

Index: pkg/analysis_server/test/search/abstract_search_domain.dart
diff --git a/pkg/analysis_server/test/search/abstract_search_domain.dart b/pkg/analysis_server/test/search/abstract_search_domain.dart
index 68c54f7a2872414cde20359dc47e4204b354dc40..bd9eaf7d7510384992aed82fa3e1b272a9b6a4b6 100644
--- a/pkg/analysis_server/test/search/abstract_search_domain.dart
+++ b/pkg/analysis_server/test/search/abstract_search_domain.dart
@@ -5,8 +5,8 @@
 import 'dart:async';
 
 import 'package:analysis_server/protocol/protocol.dart';
+import 'package:analysis_server/protocol/protocol_constants.dart';
 import 'package:analysis_server/protocol/protocol_generated.dart';
-import 'package:analysis_server/src/constants.dart';
 import 'package:analysis_server/src/search/search_domain.dart';
 import 'package:analysis_server/src/services/index/index.dart'
     show Index, createMemoryIndex;
@@ -79,7 +79,7 @@ class AbstractSearchDomainTest extends AbstractAnalysisTest {
   @override
   void processNotification(Notification notification) {
     super.processNotification(notification);
-    if (notification.event == SEARCH_RESULTS) {
+    if (notification.event == SEARCH_NOTIFICATION_RESULTS) {
       var params = new SearchResultsParams.fromNotification(notification);
       String id = params.id;
       _ResultSet resultSet = resultSets[id];