Stop using Element.unit directly.

pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart

Index: pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
diff --git a/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart b/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
index b742612c9f8e547c23b4c871874dc4027e86ce1c..e8ef23c69d4556e89177d1f2ab4f01e219b4ff40 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/convert_method_to_getter.dart
@@ -24,11 +24,13 @@ import 'package:analyzer/src/generated/source.dart';
 class ConvertMethodToGetterRefactoringImpl extends RefactoringImpl
     implements ConvertMethodToGetterRefactoring {
   final SearchEngine searchEngine;
+  final GetResolvedUnit getResolvedUnit;
   final ExecutableElement element;
 
   SourceChange change;
 
-  ConvertMethodToGetterRefactoringImpl(this.searchEngine, this.element);
+  ConvertMethodToGetterRefactoringImpl(
+      this.searchEngine, this.getResolvedUnit, this.element);
 
   @override
   String get refactoringName => 'Convert Method To Getter';
@@ -114,7 +116,7 @@ class ConvertMethodToGetterRefactoringImpl extends RefactoringImpl
     }
   }
 
-  Future _updateElementReferences(Element element) async {
+  Future<Null> _updateElementReferences(Element element) async {
     List<SearchMatch> matches = await searchEngine.searchReferences(element);
     List<SourceReference> references = getSourceReferences(matches);
     for (SourceReference reference in references) {
@@ -123,7 +125,7 @@ class ConvertMethodToGetterRefactoringImpl extends RefactoringImpl
       // prepare invocation
       MethodInvocation invocation;
       {
-        CompilationUnit refUnit = refElement.unit;
+        CompilationUnit refUnit = await getResolvedUnit(refElement);
         AstNode refNode =
             new NodeLocator(refRange.offset).searchWithin(refUnit);
         invocation = refNode.getAncestor((node) => node is MethodInvocation);