[fsp] Introduce file_system_provider::Service class for the FileSystemProvider API.

chrome/browser/chromeos/extensions/file_system_provider/file_system_provider_apitest.cc

 // Copyright 2013 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 "chrome/browser/extensions/extension_apitest.h"
 
 namespace extensions {
 
 class FileSystemProviderApiTest : public ExtensionApiTest {
  public:
   FileSystemProviderApiTest()
       // Set the channel to "trunk" since this API is restricted to trunk.
       : current_channel_(chrome::VersionInfo::CHANNEL_UNKNOWN) {
   }
 
  private:
   extensions::ScopedCurrentChannel current_channel_;
 };
 
 IN_PROC_BROWSER_TEST_F(FileSystemProviderApiTest, Mount) {
-  ASSERT_TRUE(RunPlatformAppTest("file_system_provider/mount"))
+  ASSERT_TRUE(RunPlatformAppTestWithFlags("file_system_provider/mount",
+                                          kFlagLoadAsComponent))
       << message_;
 }
 
 }  // namespace extensions