Add IR nodes needed for deferred loading.

pkg/kernel/lib/type_checker.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.type_checker;
 
 import 'ast.dart';
 import 'class_hierarchy.dart';
 import 'core_types.dart';
 import 'type_algebra.dart';
 import 'type_environment.dart';
@@ skipping 662 matching lines @@
   }
 
   @override
   DartType visitVariableSet(VariableSet node) {
     var value = visitExpression(node.value);
     checkAssignable(node.value, value, node.variable.type);
     return value;
   }
 
   @override
+  DartType visitLoadLibrary(LoadLibrary node) {
+    return environment.futureType(const DynamicType());
+  }
+
+  @override
+  DartType visitCheckLibraryIsLoaded(CheckLibraryIsLoaded node) {
+    return environment.objectType;
+  }
+
+  @override
   visitAssertStatement(AssertStatement node) {
     visitExpression(node.condition);
     if (node.message != null) {
       visitExpression(node.message);
     }
   }
 
   @override
   visitBlock(Block node) {
     node.statements.forEach(visitStatement);
@@ skipping 199 matching lines @@
   }
 
   @override
   visitLocalInitializer(LocalInitializer node) {
     visitVariableDeclaration(node.variable);
   }
 
   @override
   visitInvalidInitializer(InvalidInitializer node) {}
 }