Replace ClassHierarchy.classes with getOrderedClasses().

pkg/kernel/test/class_hierarchy_test.dart

Index: pkg/kernel/test/class_hierarchy_test.dart
diff --git a/pkg/kernel/test/class_hierarchy_test.dart b/pkg/kernel/test/class_hierarchy_test.dart
index 8cb8fa97d937a8484950d8c3207e0e64968e7a52..edaeb32a050c7e7dc67df1d0b979f013e93b9e05 100644
--- a/pkg/kernel/test/class_hierarchy_test.dart
+++ b/pkg/kernel/test/class_hierarchy_test.dart
@@ -796,6 +796,29 @@ class C implements self::B {}
     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]);