Fix for inlining async methods/getters.

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

Index: pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
diff --git a/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart b/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
index ca243c4b0673c97f2f1fa17f6b40c267787927ff..d68de947477092a705025ef737382facb5a4e749 100644
--- a/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
+++ b/pkg/analysis_server/lib/src/services/refactoring/inline_method.dart
@@ -216,6 +216,7 @@ class InlineMethodRefactoringImpl extends RefactoringImpl
   _SourcePart _methodExpressionPart;
   _SourcePart _methodStatementsPart;
   List<_ReferenceProcessor> _referenceProcessors = [];
+  Set<FunctionBody> _alreadyMadeAsync = new Set<FunctionBody>();
 
   InlineMethodRefactoringImpl(this.searchEngine, this.unit, this.offset) {
     utils = new CorrectionUtils(unit);
@@ -560,6 +561,15 @@ class _ReferenceProcessor {
     if (!_shouldProcess()) {
       return;
     }
+    // If the element being inlined is async, ensure that the function
+    // body that encloses the method is also async.
+    if (ref._methodElement.isAsynchronous) {
+      FunctionBody body = _node.getAncestor((n) => n is FunctionBody);
+      if (!body.isAsynchronous && ref._alreadyMadeAsync.add(body)) {
+        SourceRange bodyStart = rangeStartLength(body.offset, 0);
+        _addRefEdit(newSourceEdit_range(bodyStart, 'async '));
+      }
+    }
     // may be invocation of inline method
     if (nodeParent is MethodInvocation) {
       MethodInvocation invocation = nodeParent;