Use async/await in refactorings.

pkg/analysis_server/lib/src/services/refactoring/inline_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.inline_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol_server.dart' hide Element;
 import 'package:analysis_server/src/services/correction/source_range.dart';
@@ skipping 257 matching lines @@
       doSourceChange_addElementEdit(
           change,
           _methodElement,
           newSourceEdit_range(linesRange, ''));
     }
     // done
     return new Future.value(result);
   }
 
   @override
-  Future<RefactoringStatus> checkInitialConditions() {
+  Future<RefactoringStatus> checkInitialConditions() async {
     RefactoringStatus result = new RefactoringStatus();
     // prepare method information
     result.addStatus(_prepareMethod());
     if (result.hasFatalError) {
       return new Future.value(result);
     }
     // maybe operator
     if (_methodElement.isOperator) {
       result = new RefactoringStatus.fatal('Cannot inline operator.');
       return new Future.value(result);
     }
     // analyze method body
     result.addStatus(_prepareMethodParts());
     // process references
-    return searchEngine.searchReferences(_methodElement).then((references) {
-      _referenceProcessors.clear();
-      for (SearchMatch reference in references) {
-        _ReferenceProcessor processor =
-            new _ReferenceProcessor(this, reference);
-        _referenceProcessors.add(processor);
-      }
-    }).then((_) {
-      return result;
-    });
+    List<SearchMatch> references =
+        await searchEngine.searchReferences(_methodElement);
+    _referenceProcessors.clear();
+    for (SearchMatch reference in references) {
+      _ReferenceProcessor processor = new _ReferenceProcessor(this, reference);
+      _referenceProcessors.add(processor);
+    }
+    return result;
   }
 
   @override
   Future<SourceChange> createChange() {
     return new Future.value(change);
   }
 
   @override
   bool requiresPreview() => false;
 
@@ skipping 527 matching lines @@
   }
 
   void _addVariable(SimpleIdentifier node) {
     VariableElement variableElement = getLocalVariableElement(node);
     if (variableElement != null) {
       SourceRange nodeRange = rangeNode(node);
       result.addVariable(variableElement, nodeRange);
     }
   }
 }