Add Vector type to Kernel

pkg/kernel/lib/transformations/treeshaker.dart

 // Copyright (c) 2016, 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 kernel.tree_shaker;
 
 import '../ast.dart';
 import '../class_hierarchy.dart';
 import '../core_types.dart';
 import '../type_environment.dart';
@@ skipping 1015 matching lines @@
 
   visitInvalidType(InvalidType node) {}
 
   visitDynamicType(DynamicType node) {
     // TODO(asgerf): Find a suitable model for untyped externals, e.g. track
     // them to the first type boundary.
   }
 
   visitVoidType(VoidType node) {}
 
+  visitVectorType(VectorType node) {}
+
   visitInterfaceType(InterfaceType node) {
     if (isCovariant) {
       shaker._addInstantiatedExternalSubclass(node.classNode);
     }
     if (isContravariant) {
       shaker._addEscapedClass(node.classNode);
     }
     for (int i = 0; i < node.typeArguments.length; ++i) {
       DartType typeArgument = node.typeArguments[i];
       // In practice we don't get much out of analyzing variance here, so
@@ skipping 30 matching lines @@
         classNode == coreTypes.futureClass ||
         classNode == coreTypes.streamClass ||
         classNode == coreTypes.listClass ||
         classNode == coreTypes.mapClass;
   }
 }
 
 /// Exception that is thrown to stop the tree shaking analysis when a use
 /// of `dart:mirrors` is found.
 class _UsingMirrorsException {}