Use async/await in refactorings.

pkg/analysis_server/lib/src/services/refactoring/move_file.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.move_file;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/status.dart';
@@ skipping 38 matching lines @@
     return new Future.value(result);
   }
 
   @override
   Future<RefactoringStatus> checkInitialConditions() {
     RefactoringStatus result = new RefactoringStatus();
     return new Future.value(result);
   }
 
   @override
-  Future<SourceChange> createChange() {
+  Future<SourceChange> createChange() async {
     change = new SourceChange('Update File References');
     List<Source> librarySources = context.getLibrariesContaining(source);
-    return Future.forEach(librarySources, (Source librarySource) {
+    await Future.forEach(librarySources, (Source librarySource) async {
       CompilationUnitElement unitElement =
           context.getCompilationUnitElement(source, librarySource);
       if (unitElement != null) {
         // if a defining unit, update outgoing references
         library = unitElement.library;
         if (library.definingCompilationUnit == unitElement) {
           oldLibraryDir = pathContext.dirname(oldFile);
           newLibraryDir = pathContext.dirname(newFile);
           _updateUriReferences(library.imports);
           _updateUriReferences(library.exports);
           _updateUriReferences(library.parts);
         }
         // update reference to the unit
-        return searchEngine.searchReferences(unitElement).then((matches) {
-          List<SourceReference> references = getSourceReferences(matches);
-          for (SourceReference reference in references) {
-            String newUri = _computeNewUri(reference);
-            reference.addEdit(change, "'$newUri'");
-          }
-        });
+        List<SearchMatch> matches =
+            await searchEngine.searchReferences(unitElement);
+        List<SourceReference> references = getSourceReferences(matches);
+        for (SourceReference reference in references) {
+          String newUri = _computeNewUri(reference);
+          reference.addEdit(change, "'$newUri'");
+        }
       }
-    }).then((_) {
-      return change;
     });
+    return change;
   }
 
   @override
   bool requiresPreview() => false;
 
   /**
    * Computes the URI to use to reference [newFile] from [reference].
    */
   String _computeNewUri(SourceReference reference) {
     String refDir = pathContext.dirname(reference.file);
@@ skipping 57 matching lines @@
       }
     }
   }
 
   void _updateUriReferences(List<UriReferencedElement> elements) {
     for (UriReferencedElement element in elements) {
       _updateUriReference(element);
     }
   }
 }