- Fix usage of Platform.packageRoot.

pkg/analysis_server/test/integration/integration_tests.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.integration.analysis;
 
 import 'dart:async';
 import 'dart:collection';
 import 'dart:convert';
 import 'dart:io';
@@ skipping 595 matching lines @@
         findRoot(Platform.script.toFilePath(windows: Platform.isWindows));
     String serverPath = normalize(join(rootDir, 'bin', 'server.dart'));
     List<String> arguments = [];
     if (debugServer) {
       arguments.add('--debug');
     }
     if (profileServer) {
       arguments.add('--observe');
       arguments.add('--pause-isolates-on-exit');
     }
-    if (Platform.packageRoot.isNotEmpty) {
+    if (Platform.packageRoot != null) {
       arguments.add('--package-root=${Platform.packageRoot}');
     }
     arguments.add('--checked');
     arguments.add(serverPath);
     if (diagnosticPort != null) {
       arguments.add('--port');
       arguments.add(diagnosticPort.toString());
     }
     if (useAnalysisHighlight2) {
       arguments.add('--useAnalysisHighlight2');
@@ skipping 256 matching lines @@
   void populateMismatches(item, List<MismatchDescriber> mismatches);
 
   /**
    * Create a [MismatchDescriber] describing a mismatch with a simple string.
    */
   MismatchDescriber simpleDescription(String description) =>
       (Description mismatchDescription) {
         mismatchDescription.add(description);
       };
 }