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

pkg/analysis_server/test/services/refactoring/extract_method_test.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 test.services.refactoring.extract_method;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/protocol.dart';
 import 'package:analysis_server/src/services/correction/status.dart';
@@ skipping 1169 matching lines @@
     return _assertSuccessfulRefactoring('''
 dynaFunction() {}
 main() {
   var v = res(); // marker
 }
 
 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() {
   getButton().text = 'txt';
   print(getButton().text); // marker
 }
 getButton() {}
 ''');
     _createRefactoringWithSuffix('getButton().text', '); // marker');
     // apply refactoring
@@ skipping 934 matching lines @@
     return;
   }
   throw 'boo!';
 // end
 }
 ''');
     _createRefactoringForStartEndComments();
     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 {
   foo(int p) {
     switch (p) {
       case 0:
 // start
         print(0);
 // end
         break;
@@ skipping 411 matching lines @@
    * Returns a deep copy of [refactoring] parameters.
    * There was a bug masked by updating parameter instances shared between the
    * refactoring and the test.
    */
   List<RefactoringMethodParameter> _getParametersCopy() {
     return refactoring.parameters.map((p) {
       return new RefactoringMethodParameter(p.kind, p.type, p.name, id: p.id);
     }).toList();
   }
 }