Use async/await in all analysis domain tests.

pkg/analysis_server/test/analysis/reanalyze_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.analysis.reanalyze;
 
 import 'package:analysis_server/plugin/protocol/protocol.dart';
 import 'package:analysis_server/src/constants.dart';
 import 'package:analyzer/src/generated/engine.dart';
 import 'package:test_reflective_loader/test_reflective_loader.dart';
@@ skipping 26 matching lines @@
     AnalysisContext oldContext = contexts[0];
     // Reanalyze should cause a brand new context to be built.
     Request request = new Request("0", ANALYSIS_REANALYZE);
     handleSuccessfulRequest(request);
     contexts = server.folderMap.values.toList();
     expect(contexts, hasLength(1));
     AnalysisContext newContext = contexts[0];
     expect(newContext, isNot(same(oldContext)));
   }
 
-  test_reanalyze_with_overlay() {
+  test_reanalyze_with_overlay() async {
     createProject();
     resourceProvider.newFolder(testFolder);
     resourceProvider.newFile(testFile, 'main() {}');
-    return waitForTasksFinished().then((_) {
-      // Update the content with an overlay that contains a syntax error.
-      server.updateContent('1', {testFile: new AddContentOverlay('main() {')});
-      return waitForTasksFinished();
-    }).then((_) {
-      // Verify that the syntax error was detected.
+    await waitForTasksFinished();
+    // Update the content with an overlay that contains a syntax error.
+    server.updateContent('1', {testFile: new AddContentOverlay('main() {')});
+    await waitForTasksFinished();
+    // Verify that the syntax error was detected.
+    {
       List<AnalysisError> errors = filesErrors[testFile];
       expect(errors, hasLength(1));
-      // Remove testFile from filesErrors so that we'll notice when the file is
-      // re-analyzed.
-      filesErrors.remove(testFile);
-      // Reanalyze.
-      server.reanalyze(null);
-      return waitForTasksFinished();
-    }).then((_) {
-      // The file should have been reanalyzed.
-      expect(filesErrors, contains(testFile));
-      // Verify that the syntax error is present (this indicates that the
-      // content introduced by the call to updateContent is still in effect).
+    }
+    // Remove testFile from filesErrors so that we'll notice when the file is
+    // re-analyzed.
+    filesErrors.remove(testFile);
+    // Reanalyze.
+    server.reanalyze(null);
+    await waitForTasksFinished();
+    // The file should have been reanalyzed.
+    expect(filesErrors, contains(testFile));
+    // Verify that the syntax error is present (this indicates that the
+    // content introduced by the call to updateContent is still in effect).
+    {
       List<AnalysisError> errors = filesErrors[testFile];
       expect(errors, hasLength(1));
-    });
+    }
   }
 }