update analysis server spec and regen files

pkg/analysis_server/test/integration/integration_test_methods.dart

Index: pkg/analysis_server/test/integration/integration_test_methods.dart
diff --git a/pkg/analysis_server/test/integration/integration_test_methods.dart b/pkg/analysis_server/test/integration/integration_test_methods.dart
index b21b103da2bba655f9c76f16dcf4e328d520b24d..2158ed6d9fec2be709c10092948e4345e92acb81 100644
--- a/pkg/analysis_server/test/integration/integration_test_methods.dart
+++ b/pkg/analysis_server/test/integration/integration_test_methods.dart
@@ -468,13 +468,15 @@ abstract class IntegrationTestMixin {
    *
    *   A table mapping the files whose content has changed to a description of
    *   the content change.
+   *
+   * Returns
    */
-  Future sendAnalysisUpdateContent(Map<String, dynamic> files) {
+  Future<AnalysisUpdateContentResult> sendAnalysisUpdateContent(Map<String, dynamic> files) {
     var params = new AnalysisUpdateContentParams(files).toJson();
     return server.send("analysis.updateContent", params)
         .then((result) {
-      expect(result, isNull);
-      return null;
+      ResponseDecoder decoder = new ResponseDecoder(null);
+      return new AnalysisUpdateContentResult.fromJson(decoder, 'result', result);
     });
   }