Use List instead of Link in the type system.

tests/compiler/dart2js/resolver_test.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.
 
 import "package:expect/expect.dart";
 import 'dart:async';
 import "package:async_helper/async_helper.dart";
 import 'dart:collection';
 
 import "../../../sdk/lib/_internal/compiler/implementation/resolution/resolution.dart";
 import "compiler_helper.dart";
 import "parser_helper.dart";
 
 import '../../../sdk/lib/_internal/compiler/implementation/dart_types.dart';
+import 'link_helper.dart';
 
 Node buildIdentifier(String name) => new Identifier(scan(name));
 
 Node buildInitialization(String name) =>
   parseBodyCode('$name = 1',
       (parser, tokens) => parser.parseOptionallyInitializedIdentifier(tokens));
 
 createLocals(List variables) {
-  var locals = [];
+  var locals = <Node>[];
   for (final variable in variables) {
     String name = variable[0];
     bool init = variable[1];
     if (init) {
       locals.add(buildInitialization(name));
     } else {
       locals.add(buildIdentifier(name));
     }
   }
-  var definitions = new NodeList(null, new Link.fromList(locals), null, null);
+  var definitions = new NodeList(null, LinkFromList(locals), null, null);
   return new VariableDefinitions(null, Modifiers.EMPTY, definitions);
 }
 
 testLocals(List variables) {
   MockCompiler compiler = new MockCompiler();
   ResolverVisitor visitor = compiler.resolverVisitor();
   Element element = visitor.visit(createLocals(variables));
   // A VariableDefinitions does not have an element.
   Expect.equals(null, element);
   Expect.equals(variables.length, map(visitor).length);
@@ skipping 77 matching lines @@
   Expect.equals(MessageKind.MULTI_INHERITANCE,
                 compiler.crashes[0].message.kind);
 }
 
 testTypeVariables() {
   matchResolvedTypes(visitor, text, name, expectedElements) {
     VariableDefinitions definition = parseStatement(text);
     visitor.visit(definition.type);
     InterfaceType type = visitor.mapping.getType(definition.type);
     Expect.equals(definition.type.typeArguments.slowLength(),
-                  length(type.typeArguments));
+                  type.typeArguments.length);
     int index = 0;
-    Link<DartType> arguments = type.typeArguments;
-    while (!arguments.isEmpty) {
+    for (DartType argument in type.typeArguments) {
       Expect.equals(true, index < expectedElements.length);
-      Expect.equals(expectedElements[index], arguments.head.element);
+      Expect.equals(expectedElements[index], argument.element);
       index++;
-      arguments = arguments.tail;
     }
     Expect.equals(index, expectedElements.length);
   }
 
   MockCompiler compiler = new MockCompiler();
   ResolverVisitor visitor = compiler.resolverVisitor();
   compiler.parseScript('class Foo<T, U> {}');
   ClassElement foo = compiler.mainApp.find('Foo');
   matchResolvedTypes(visitor, 'Foo<int, String> x;', 'Foo',
                      [compiler.intClass, compiler.stringClass]);
@@ skipping 861 matching lines @@
       }""";
   asyncTest(() => compileScript(script2).then((compiler) {
     expect(compiler,
         [MessageKind.CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS],
         [MessageKind.CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_CONSTRUCTOR,
          MessageKind.CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_CONSTRUCTOR,
          MessageKind.CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_FIELD,
          MessageKind.CONST_CONSTRUCTOR_WITH_NONFINAL_FIELDS_FIELD]);
   }));
 }