Remove false positive from override hint (issue 27046)

pkg/analyzer/lib/src/task/dart.dart

 // Copyright (c) 2015, 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 analyzer.src.task.dart;
 
 import 'dart:collection';
 
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart';
@@ skipping 3230 matching lines @@
           new UsedLocalElements.merge(usedLocalElementsList);
       UnusedLocalElementsVerifier visitor =
           new UnusedLocalElementsVerifier(errorListener, usedElements);
       unitElement.accept(visitor);
     }
     // Dart2js analysis.
     if (analysisOptions.dart2jsHint) {
       unit.accept(new Dart2JSVerifier(errorReporter));
     }
     // Dart best practices.
-    InheritanceManager inheritanceManager =
-        new InheritanceManager(libraryElement);
+    InheritanceManager inheritanceManager = new InheritanceManager(
+        libraryElement,
+        includeAbstractFromSuperclasses: true);
     TypeProvider typeProvider = getRequiredInput(TYPE_PROVIDER_INPUT);
 
     unit.accept(new BestPracticesVerifier(
         errorReporter, typeProvider, libraryElement,
         typeSystem: typeSystem));
     unit.accept(new OverrideVerifier(errorReporter, inheritanceManager));
     // Find to-do comments.
     new ToDoFinder(errorReporter).findIn(unit);
     //
     // Record outputs.
@@ skipping 3319 matching lines @@
 
   @override
   bool moveNext() {
     if (_newSources.isEmpty) {
       return false;
     }
     currentTarget = _newSources.removeLast();
     return true;
   }
 }