Introduces the new syntax for deferred loading

sdk/lib/_internal/compiler/implementation/tree/nodes.dart

Index: sdk/lib/_internal/compiler/implementation/tree/nodes.dart
diff --git a/sdk/lib/_internal/compiler/implementation/tree/nodes.dart b/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
index 40ec287f84ceee86e5c1c5851e93e7734ccb49ca..d74f51f9c8f0fdcdc084cb4799cfb6defe656e5e 100644
--- a/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
+++ b/sdk/lib/_internal/compiler/implementation/tree/nodes.dart
@@ -1801,18 +1801,18 @@ abstract class LibraryDependency extends LibraryTag {
 class Import extends LibraryDependency {
   final Identifier prefix;
   final Token importKeyword;
+  final bool isDeferred;
 
   Import(this.importKeyword, StringNode uri,
          this.prefix, NodeList combinators,
-         Link<MetadataAnnotation> metadata)
+         Link<MetadataAnnotation> metadata,
+         {this.isDeferred})
       : super(uri, combinators, metadata);
 
   bool get isImport => true;
 
   Import asImport() => this;
 
-  Token get asKeyword => prefix == null ? null : uri.getEndToken().next;
-
   accept(Visitor visitor) => visitor.visitImport(this);
 
   visitChildren(Visitor visitor) {