Support @JS with path expressions.

lib/src/compiler/code_generator.dart

 // Copyright (c) 2015, 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.
 
 import 'dart:collection' show HashMap, HashSet;
 import 'dart:math' show min, max;
 
 import 'package:analyzer/analyzer.dart' hide ConstantEvaluator;
 import 'package:analyzer/dart/ast/ast.dart';
 import 'package:analyzer/dart/ast/token.dart' show Token, TokenType;
@@ skipping 2327 matching lines @@
     }
 
     return _emitTopLevelName(element);
   }
 
   JS.PropertyAccess _emitTopLevelName(Element e, {String suffix: ''}) {
     if (e is TopLevelVariableElement &&
         e.getter != null &&
         findAnnotation(e.getter, isPublicJSAnnotation) != null) {
       var annotationName = getAnnotationName(e.getter, isPublicJSAnnotation);
-      var name = js.string(annotationName ?? e.name);
-      return new JS.PropertyAccess(_self, name);
+      var name = annotationName ?? e.name;
+      JS.PropertyAccess result = null;
+      for (var segment in name.split('.')) {
+        result = new JS.PropertyAccess(result ?? _self, js.string(segment));
+      }
+      return result;
     }
     String name = getJSExportName(e) + suffix;
     return new JS.PropertyAccess(
         emitLibraryName(e.library), _propertyName(name));
   }
 
   @override
   JS.Expression visitAssignmentExpression(AssignmentExpression node) {
     var left = node.leftHandSide;
     var right = node.rightHandSide;
@@ skipping 2129 matching lines @@
 }
 
 bool isLibraryPrefix(Expression node) =>
     node is SimpleIdentifier && node.staticElement is PrefixElement;
 
 LibraryElement _getLibrary(AnalysisContext c, String uri) =>
     c.computeLibraryElement(c.sourceFactory.forUri(uri));
 
 bool _isDartRuntime(LibraryElement l) =>
     l.isInSdk && l.source.uri.toString() == 'dart:_runtime';