Use List instead of Link in the type system.

sdk/lib/_internal/compiler/implementation/elements/elements.dart

 // Copyright (c) 2012, 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 elements;
 
 
 import '../tree/tree.dart';
 import '../util/util.dart';
 import '../resolution/resolution.dart';
@@ skipping 1038 matching lines @@
    * this distinction, we can print the raw type with type arguments only when
    * the input source has used explicit type arguments.
    */
   GenericType get rawType;
 
   /**
    * The type variables declared on this declaration. The type variables are not
    * available until the type of the element has been computed through
    * [computeType].
    */
-  Link<DartType> get typeVariables;
+  List<DartType> get typeVariables;
 
   bool get isResolved;
 
   int get resolutionState;
 
   void ensureResolved(Compiler compiler);
 }
 
 abstract class ClassElement extends TypeDeclarationElement
     implements ScopeContainerElement {
@@ skipping 84 matching lines @@
 
   void forEachInstanceField(void f(ClassElement enclosingClass,
                                    FieldElement field),
                             {bool includeSuperAndInjectedMembers: false});
 
   /// Similar to [forEachInstanceField] but visits static fields.
   void forEachStaticField(void f(ClassElement enclosingClass, Element field));
 
   void forEachBackendMember(void f(Element member));
 
-  Link<DartType> computeTypeParameters(Compiler compiler);
+  List<DartType> computeTypeParameters(Compiler compiler);
 
   /// Looks up the member [name] in this class.
   Member lookupClassMember(Name name);
 
   /// Calls [f] with each member of this class.
   void forEachClassMember(f(Member member));
 
   /// Looks up the member [name] in the interface of this class.
   MemberSignature lookupInterfaceMember(Name name);
 
@@ skipping 186 matching lines @@
   bool get isDeclaredByField;
 
   /// Returns `true` if this member is abstract.
   bool get isAbstract;
 
   /// If abstract, [implementation] points to the overridden concrete member,
   /// if any. Otherwise [implementation] points to the member itself.
   Member get implementation;
 }