Get code to format from 'overlayState' or from the Source.

pkg/analysis_server/lib/src/edit/edit_domain.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 edit.domain;
 
 import 'dart:async';
 
 import 'package:analysis_server/plugin/edit/assist/assist_core.dart';
 import 'package:analysis_server/plugin/edit/fix/fix_core.dart';
@@ skipping 51 matching lines @@
    */
   EditDomainHandler(this.server) {
     searchEngine = server.searchEngine;
     _newRefactoringManager();
   }
 
   Response format(Request request) {
     EditFormatParams params = new EditFormatParams.fromRequest(request);
     String file = params.file;
 
-    ContextSourcePair contextSource = server.getContextSourcePair(file);
-
-    engine.AnalysisContext context = contextSource.context;
-    if (context == null) {
-      return new Response.formatInvalidFile(request);
-    }
-
-    Source source = contextSource.source;
-    engine.TimestampedData<String> contents;
+    String unformattedSource;
     try {
-      contents = context.getContents(source);
+      Source source = server.resourceProvider.getFile(file).createSource();
+      unformattedSource = server.overlayState.getContents(source);
+      unformattedSource ??= source.contents.data;
     } catch (e) {
       return new Response.formatInvalidFile(request);
     }
 
-    String unformattedSource = contents.data;
-
     int start = params.selectionOffset;
     int length = params.selectionLength;
 
     // No need to preserve 0,0 selection
     if (start == 0 && length == 0) {
       start = null;
       length = null;
     }
 
     SourceCode code = new SourceCode(unformattedSource,
@@ skipping 715 matching lines @@
     }
     return new RefactoringStatus();
   }
 }
 
 /**
  * [_RefactoringManager] throws instances of this class internally to stop
  * processing in a manager that was reset.
  */
 class _ResetError {}