Compute isSubtype and isSubclass using ClassSet/ClassHierarchyNode

pkg/compiler/lib/src/universe/class_set.dart

Index: pkg/compiler/lib/src/universe/class_set.dart
diff --git a/pkg/compiler/lib/src/universe/class_set.dart b/pkg/compiler/lib/src/universe/class_set.dart
index 3eaf8cbe0af8f0420e320a777876f78110b583dc..9df3c2d5b1366f4102f90fdb6a45db6b4164c143 100644
--- a/pkg/compiler/lib/src/universe/class_set.dart
+++ b/pkg/compiler/lib/src/universe/class_set.dart
@@ -228,6 +228,11 @@ class ClassHierarchyNode {
     return false;
   }
 
+  /// Returns `true` if `other.cls` is a subclass of [cls].
+  bool hasSubclass(ClassHierarchyNode other) {
+    return contains(other);
+  }
+
   /// `true` if [cls] has been directly, indirectly, or abstractly instantiated.
   bool get isInstantiated =>
       isExplicitlyInstantiated || isIndirectlyInstantiated;
@@ -480,6 +485,20 @@ class ClassSet {
 
   ClassEntity get cls => node.cls;
 
+  /// Returns `true` if `other.cls` is a subclass of [cls].
+  bool hasSubclass(ClassHierarchyNode other) => node.hasSubclass(other);
+
+  /// Returns `true` if `other.cls` is a subtype of [cls].
+  bool hasSubtype(ClassHierarchyNode other) {
+    if (hasSubclass(other)) return true;
+    if (_subtypes != null) {
+      for (ClassHierarchyNode subtypeNode in _subtypes) {
+        if (subtypeNode.hasSubclass(other)) return true;
+      }
+    }
+    return false;
+  }
+
   /// Returns the number of directly instantiated subtypes of [cls].
   int get instantiatedSubtypeCount {
     int count = node.instantiatedSubclassCount;