Push add*Edit helpers into SourceChange.

pkg/analysis_server/lib/src/services/refactoring/extract_method.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.
 
 library services.src.refactoring.extract_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart' hide Element;
 import 'package:analysis_server/src/services/correction/name_suggestion.dart';
@@ skipping 258 matching lines @@
           sb.write(')');
         }
         invocationSource = sb.toString();
         // statements as extracted with their ";", so add new after invocation
         if (_selectionStatements != null) {
           invocationSource += ';';
         }
       }
       // add replace edit
       SourceEdit edit = new SourceEdit.range(range, invocationSource);
-      addElementSourceChange(change, unitElement, edit);
+      change.addElementEdit(unitElement, edit);
     }
     // add method declaration
     {
       // prepare environment
       String prefix = utils.getNodePrefix(_parentMember);
       String eol = utils.endOfLine;
       // prepare annotations
       String annotations = '';
       {
         // may be "static"
@@ skipping 36 matching lines @@
                 '${prefix}  return ${_returnVariableName};$eol';
           }
           declarationSource += '${prefix}}';
         }
       }
       // insert declaration
       if (declarationSource != null) {
         int offset = _parentMember.end;
         SourceEdit edit =
             new SourceEdit(offset, 0, '${eol}${eol}${prefix}${declarationSource}');
-        addElementSourceChange(change, unitElement, edit);
+        change.addElementEdit(unitElement, edit);
       }
     }
     // done
     return new Future.value(change);
   }
 
   @override
   bool requiresPreview() => false;
 
   /**
@@ skipping 751 matching lines @@
 
 /**
  * Generalized version of some source, in which references to the specific
  * variables are replaced with pattern variables, with back mapping from the
  * pattern to the original variable names.
  */
 class _SourcePattern {
   String patternSource;
   Map<String, String> originalToPatternNames = {};
 }