Replace ClassHierarchy.classes with getOrderedClasses().

pkg/kernel/test/class_hierarchy_test.dart

 // Copyright (c) 2017, 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.
 
 import 'package:kernel/ast.dart';
 import 'package:kernel/class_hierarchy.dart';
 import 'package:kernel/core_types.dart';
 import 'package:kernel/src/incremental_class_hierarchy.dart';
 import 'package:kernel/testing/mock_sdk_program.dart';
 import 'package:kernel/text/ast_to_text.dart';
@@ skipping 778 matching lines @@
     expect(hierarchy.getInterfaceMember(b, aMethodName), aMethod);
     expect(hierarchy.getInterfaceMember(b, bMethodName), bMethod);
     expect(hierarchy.getInterfaceMember(b, aSetterName, setter: true), aSetter);
     expect(hierarchy.getInterfaceMember(b, bSetterName, setter: true), bSetter);
     expect(hierarchy.getInterfaceMember(c, aMethodName), aMethod);
     expect(hierarchy.getInterfaceMember(c, bMethodName), bMethod);
     expect(hierarchy.getInterfaceMember(c, aSetterName, setter: true), aSetter);
     expect(hierarchy.getInterfaceMember(c, bSetterName, setter: true), bSetter);
   }
 
+  void test_getOrderedClasses() {
+    var a = addClass(new Class(name: 'A', supertype: objectSuper));
+    var b = addClass(new Class(name: 'B', supertype: a.asThisSupertype));
+    var c = addClass(new Class(name: 'C', supertype: b.asThisSupertype));
+
+    void assertOrderOfClasses(List<Class> unordered, List<Class> expected) {
+      var ordered = hierarchy.getOrderedClasses(unordered).toList();
+      var lastIndex = -1;
+      for (var node in expected) {
+        var index = ordered.indexOf(node);
+        expect(index, greaterThan(lastIndex));
+        lastIndex = index;
+      }
+    }
+
+    assertOrderOfClasses([a, b, c], [a, b, c]);
+    assertOrderOfClasses([b, a, c], [a, b, c]);
+    assertOrderOfClasses([a, c, b], [a, b, c]);
+    assertOrderOfClasses([b, c, a], [a, b, c]);
+    assertOrderOfClasses([c, a, b], [a, b, c]);
+    assertOrderOfClasses([c, b, a], [a, b, c]);
+  }
+
   void test_getRankedSuperclasses() {
     var a = addImplementsClass('A', []);
     var b = addImplementsClass('B', [a]);
     var c = addImplementsClass('C', [a]);
     var d = addImplementsClass('D', [c]);
     var e = addImplementsClass('E', [b, d]);
 
     _assertTestLibraryText('''
 class A {}
 class B implements self::A {}
@@ skipping 73 matching lines @@
     actualText = actualText.replaceAll(' extends core::Object', '');
 
 //    if (actualText != expectedText) {
 //      print('-------- Actual --------');
 //      print(actualText + '------------------------');
 //    }
 
     expect(actualText, expectedText);
   }
 }