Add await/async when a method with 'await' in its body is extracted.

pkg/analysis_server/test/services/refactoring/extract_method_test.dart

Index: pkg/analysis_server/test/services/refactoring/extract_method_test.dart
diff --git a/pkg/analysis_server/test/services/refactoring/extract_method_test.dart b/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
index 113e3742850bf9f50a872a7eb99492e2b0e316a1..68ec6ec0403b2809263754adb9f22996193ab0d2 100644
--- a/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
+++ b/pkg/analysis_server/test/services/refactoring/extract_method_test.dart
@@ -1187,6 +1187,29 @@ res() => dynaFunction();
 ''');
   }
 
+  test_singleExpression_hasAwait() {
+    indexTestUnit('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+  int v = await getValue();
+  print(v);
+}
+''');
+    _createRefactoringForString('await getValue()');
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+  int v = await res();
+  print(v);
+}
+
+Future<int> res() async => await getValue();
+''');
+  }
+
   test_singleExpression_ignore_assignmentLeftHandSize() {
     indexTestUnit('''
 main() {
@@ -2141,6 +2164,133 @@ main(int p) {
     await assertRefactoringConditionsOK();
   }
 
+  test_statements_hasAwait_dynamicReturnType() {
+    indexTestUnit('''
+import 'dart:async';
+Future getValue() => 42;
+main() async {
+// start
+  var v = await getValue();
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:async';
+Future getValue() => 42;
+main() async {
+// start
+  var v = await res();
+// end
+  print(v);
+}
+
+Future res() async {
+  var v = await getValue();
+  return v;
+}
+''');
+  }
+
+  test_statements_hasAwait_expression() {
+    indexTestUnit('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+// start
+  int v = await getValue();
+  v += 2;
+// end
+  print(v);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+// start
+  int v = await res();
+// end
+  print(v);
+}
+
+Future<int> res() async {
+  int v = await getValue();
+  v += 2;
+  return v;
+}
+''');
+  }
+
+  test_statements_hasAwait_forEach() {
+    indexTestUnit('''
+import 'dart:async';
+Stream<int> getValueStream() => null;
+main() async {
+// start
+  int sum = 0;
+  await for (int v in getValueStream()) {
+    sum += v;
+  }
+// end
+  print(sum);
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:async';
+Stream<int> getValueStream() => null;
+main() async {
+// start
+  int sum = await res();
+// end
+  print(sum);
+}
+
+Future<int> res() async {
+  int sum = 0;
+  await for (int v in getValueStream()) {
+    sum += v;
+  }
+  return sum;
+}
+''');
+  }
+
+  test_statements_hasAwait_voidReturnType() {
+    indexTestUnit('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+// start
+  int v = await getValue();
+  print(v);
+// end
+}
+''');
+    _createRefactoringForStartEndComments();
+    // apply refactoring
+    return _assertSuccessfulRefactoring('''
+import 'dart:async';
+Future<int> getValue() => 42;
+main() async {
+// start
+  await res();
+// end
+}
+
+Future res() async {
+  int v = await getValue();
+  print(v);
+}
+''');
+  }
+
   test_statements_inSwitchMember() {
     indexTestUnit('''
 class A {