Decouple TypeMask from ClassElement

pkg/compiler/lib/src/types/forwarding_type_mask.dart

 // Copyright (c) 2013, 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.
 
 part of masks;
 
 /**
  * A type mask that wraps an other one, and delegate all its
  * implementation methods to it.
  */
@@ skipping 36 matching lines @@
   }
 
   bool containsOnlyBool(ClosedWorld closedWorld) {
     return forwardTo.containsOnlyBool(closedWorld);
   }
 
   bool containsOnlyString(ClosedWorld closedWorld) {
     return forwardTo.containsOnlyString(closedWorld);
   }
 
-  bool containsOnly(ClassElement element) {
-    return forwardTo.containsOnly(element);
+  bool containsOnly(Entity cls) {
+    return forwardTo.containsOnly(cls);
   }
 
-  bool satisfies(ClassElement cls, ClosedWorld closedWorld) {
+  bool satisfies(Entity cls, ClosedWorld closedWorld) {
     return forwardTo.satisfies(cls, closedWorld);
   }
 
-  bool contains(ClassElement type, ClosedWorld closedWorld) {
-    return forwardTo.contains(type, closedWorld);
+  bool contains(Entity cls, ClosedWorld closedWorld) {
+    return forwardTo.contains(cls, closedWorld);
   }
 
   bool containsAll(ClosedWorld closedWorld) {
     return forwardTo.containsAll(closedWorld);
   }
 
-  ClassElement singleClass(ClosedWorld closedWorld) {
+  Entity singleClass(ClosedWorld closedWorld) {
     return forwardTo.singleClass(closedWorld);
   }
 
   TypeMask union(other, ClosedWorld closedWorld) {
     if (this == other) {
       return this;
     } else if (equalsDisregardNull(other)) {
       return other.isNullable ? other : this;
     } else if (other.isEmptyOrNull) {
       return other.isNullable ? this.nullable() : this;
@@ skipping 29 matching lines @@
       return forwardTo == other.forwardTo.nonNullable();
     }
   }
 
   bool operator ==(other) {
     return equalsDisregardNull(other) && isNullable == other.isNullable;
   }
 
   int get hashCode => throw "Subclass should implement hashCode getter";
 }