Implement cascaded calls.

lib/compiler/implementation/resolver.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.
 
 interface TreeElements {
   Element operator[](Node node);
   Selector getSelector(Send send);
 }
 
 class TreeElementMapping implements TreeElements {
@@ skipping 654 matching lines @@
       // fields they reference are visible, but must be resolved independently.
       if (element.kind == ElementKind.FIELD_PARAMETER) {
         useElement(parameterNode, element);
       } else {
         defineElement(variableDefinitions.definitions.nodes.head, element);
       }
       parameterNodes = parameterNodes.tail;
     });
   }
 
+  visitCascade(Cascade node) {
+    visit(node.expression);
+  }
+
+  visitCascadeReceiver(CascadeReceiver node) {
+    visit(node.expression);
+  }
+
   Element visitClassNode(ClassNode node) {
     cancel(node, "shouldn't be called");
   }
 
   visitIn(Node node, Scope scope) {
     context = scope;
     Element element = visit(node);
     context = context.parent;
     return element;
   }
@@ skipping 1107 matching lines @@
 
   TopScope(LibraryElement library) : super(null, library);
   Element lookup(SourceString name) {
     return library.find(name);
   }
 
   Element add(Element element) {
     throw "Cannot add an element in the top scope";
   }
 }