Fix filesystem API file_handlers to work for drive on ChromeOS.

chrome/browser/chromeos/extensions/external_filesystem_apitest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/bind.h"
 #include "base/file_util.h"
 #include "base/files/file_path.h"
 #include "base/files/scoped_temp_dir.h"
 #include "base/json/json_file_value_serializer.h"
 #include "base/memory/scoped_ptr.h"
@@ skipping 494 matching lines @@
   // Configure the drive service to return only one search result at a time
   // to simulate paginated searches.
   fake_drive_service_->set_default_max_results(1);
   EXPECT_TRUE(RunFileSystemExtensionApiTest(
       "file_browser/drive_search_test",
       FILE_PATH_LITERAL("manifest.json"),
       "",
       FLAGS_NONE)) << message_;
 }
 
+IN_PROC_BROWSER_TEST_F(DriveFileSystemExtensionApiTest, AppFileHanlder) {
+  EXPECT_TRUE(RunFileSystemExtensionApiTest(
+      "file_browser/handler_test_runner",
+      FILE_PATH_LITERAL("manifest_v2.json"),
+      "file_browser/app_file_handler",
+      FLAGS_USE_FILE_HANDLER)) << message_;
+}
+
 }  // namespace