Fix for opening SDK sources.

pkg/analysis_server/test/domain_analysis_test.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 test.domain.analysis;
 
 import 'dart:async';
 
 import 'package:analysis_server/src/analysis_server.dart';
 import 'package:analysis_server/src/computer/error.dart';
@@ skipping 264 matching lines @@
     helper.createSingleFileProject('int V = 42;');
     return helper.waitForOperationsFinished().then((_) {
       String noFile = '/no-such-file.dart';
       helper.addAnalysisSubscriptionHighlights(noFile);
       return helper.waitForOperationsFinished().then((_) {
         var highlights = helper.getHighlights(noFile);
         expect(highlights, isEmpty);
       });
     });
   });
+
+  test('after analysis, SDK file', () {
+    AnalysisTestHelper helper = new AnalysisTestHelper();
+    helper.createSingleFileProject('''
+main() {
+  print(42);
+}
+''');
+    return helper.waitForOperationsFinished().then((_) {
+      String file = '/lib/core/core.dart';
+      helper.addAnalysisSubscriptionNavigation(file);
+      return helper.waitForOperationsFinished().then((_) {
+        var navigationRegions = helper.getNavigation(file);
+        expect(navigationRegions, isNot(isEmpty));
+      });
+    });
+  });
 }
 
 
 int _getSafeInt(Map<String, Object> json, String key, int defaultValue) {
   Object value = json[key];
   if (value is int) {
     return value;
   }
   return defaultValue;
 }
@@ skipping 270 matching lines @@
     return waitForServerOperationsPerformed(server);
   }
 
   static String _getCodeString(code) {
     if (code is List<String>) {
       code = code.join('\n');
     }
     return code as String;
   }
 }