test.py: Add 'Cache-Control' header to http responses: enable browsers to cache resources

tools/testing/dart/http_server.dart

 // Copyright (c) 2013, 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 http_server;
 
 import 'dart:async';
 import 'dart:io';
 import 'dart:isolate';
 import 'test_suite.dart';  // For TestUtils.
@@ skipping 70 matching lines @@
       DebugLogger.info('Server listening on port ${servers.crossOriginPort}');
     });
   }
 }
 
 /**
  * Runs a set of servers that are initialized specifically for the needs of our
  * test framework, such as dealing with package-root.
  */
 class TestingServers {
+  static final _CACHE_EXPIRATION_IN_SECONDS = 30;
   static final _HARMLESS_REQUEST_PATH_ENDINGS = [
     "/apple-touch-icon.png",
     "/apple-touch-icon-precomposed.png",
     "/favicon.ico",
     "/foo",
     "/bar",
     "/NonExistingFile",
     "/hahaURL",
   ];
 
@@ skipping 58 matching lines @@
       onError: (e) {
         DebugLogger.error('HttpServer: an error occured', e);
       });
       _serverList.add(httpServer);
     });
   }
 
   void _handleFileOrDirectoryRequest(HttpRequest request,
                                      HttpResponse response,
                                      int allowedPort) {
+    // Enable browsers to cache file/directory responses.
+    response.headers.set("Cache-Control",
+                         "max-age=$_CACHE_EXPIRATION_IN_SECONDS");
     var path = _getFilePathFromRequestPath(request.uri.path);
     if (path != null) {
       var file = new File.fromPath(path);
       file.exists().then((exists) {
         if (exists) {
           _sendFileContent(request, response, allowedPort, path, file);
         } else {
           var directory = new Directory.fromPath(path);
           directory.exists().then((exists) {
             if (exists) {
@@ skipping 204 matching lines @@
 class _Entry {
   final String name;
   final String displayName;
 
   _Entry(this.name, this.displayName);
 
   int compareTo(_Entry other) {
     return name.compareTo(other.name);
   }
 }