Support is/as expressions in analyzer2dart.

pkg/analyzer2dart/lib/src/cps_generator.dart

 // Copyright (c) 2014, 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 analyzer2dart.cps_generator;
 
 import 'package:analyzer/analyzer.dart';
 
 import 'package:compiler/implementation/dart_types.dart' as dart2js;
 import 'package:compiler/implementation/elements/elements.dart' as dart2js;
@@ skipping 325 matching lines @@
                        buildBody: subbuild(node.body),
                        buildUpdate: subbuildSequence(node.updaters));
   }
 
   @override
   visitWhileStatement(WhileStatement node) {
     // TODO(johnniwinther): Support `while` as a jump target.
     irBuilder.buildWhile(buildCondition: subbuild(node.condition),
                          buildBody: subbuild(node.body));
   }
+
+  @override
+  ir.Primitive visitIsExpression(IsExpression node) {
+    return irBuilder.buildTypeOperator(
+        visit(node.expression),
+        converter.convertType(node.type.type),
+        isTypeTest: true,
+        isNotCheck: node.notOperator != null);
+  }
+
+  @override
+  ir.Primitive visitAsExpression(AsExpression node) {
+    return irBuilder.buildTypeOperator(
+        visit(node.expression),
+        converter.convertType(node.type.type),
+        isTypeTest: false);
+  }
 }