update analysis server spec and regen files

pkg/analysis_server/test/integration/integration_test_methods.dart

 // Copyright (c) 2014, 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.
 //
 // This file has been automatically generated.  Please do not edit it manually.
 // To regenerate the file, use the script
 // "pkg/analysis_server/tool/spec/generate_files".
 
 /**
  * Convenience methods for running integration tests
@@ skipping 450 matching lines @@
    * content, even if the files do not exist on the filesystem or if the file
    * path represents the path to a directory on the filesystem.
    *
    * Parameters
    *
    * files ( Map<FilePath, AddContentOverlay | ChangeContentOverlay |
    * RemoveContentOverlay> )
    *
    *   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);
     });
   }
 
   /**
    * Update the options controlling analysis based on the given set of options.
    * Any options that are not included in the analysis options will not be
    * changed. If there are options in the analysis options that are not valid,
    * they will be silently ignored.
    *
    * Parameters
@@ skipping 1054 matching lines @@
       case "execution.launchData":
         expect(params, isExecutionLaunchDataParams);
         _onExecutionLaunchData.add(new ExecutionLaunchDataParams.fromJson(decoder, 'params', params));
         break;
       default:
         fail('Unexpected notification: $event');
         break;
     }
   }
 }