[fsp] Let extensions decide about the file system id.

chrome/browser/chromeos/extensions/file_manager/private_api_util.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/chromeos/extensions/file_manager/private_api_util.h"
 
 #include <string>
 
 #include "base/files/file_path.h"
 #include "base/message_loop/message_loop.h"
@@ skipping 120 matching lines @@
   // TODO(kinaba): fill appropriate information once multi-profile support is
   // implemented.
   volume_metadata->profile.display_name = profile->GetProfileName();
   volume_metadata->profile.is_current_profile = true;
 
   if (!volume_info.source_path.empty()) {
     volume_metadata->source_path.reset(
         new std::string(volume_info.source_path.AsUTF8Unsafe()));
   }
 
-  volume_metadata->extension_id.reset(
-      new std::string(volume_info.extension_id));
+  if (volume_info.type == VOLUME_TYPE_PROVIDED) {
+    volume_metadata->extension_id.reset(
+        new std::string(volume_info.extension_id));
+
+    volume_metadata->file_system_id.reset(
+        new std::string(volume_info.file_system_id));
+  }
 
   volume_metadata->volume_label.reset(
       new std::string(volume_info.volume_label));
 
   switch (volume_info.type) {
     case VOLUME_TYPE_GOOGLE_DRIVE:
       volume_metadata->volume_type =
           file_browser_private::VOLUME_TYPE_DRIVE;
       break;
     case VOLUME_TYPE_DOWNLOADS_DIRECTORY:
@@ skipping 133 matching lines @@
 
 drive::EventLogger* GetLogger(Profile* profile) {
   drive::DriveIntegrationService* service =
       drive::DriveIntegrationServiceFactory::FindForProfileRegardlessOfStates(
           profile);
   return service ? service->event_logger() : NULL;
 }
 
 }  // namespace util
 }  // namespace file_manager