SyncFS: -1 GDataErrorCode should be handled gracefully

chrome/browser/sync_file_system/drive_file_sync_util.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 "chrome/browser/sync_file_system/drive_file_sync_util.h"
 
 #include "base/logging.h"
 
 namespace sync_file_system {
 
@@ skipping 38 matching lines @@
     case google_apis::HTTP_FORBIDDEN:
     case google_apis::HTTP_LENGTH_REQUIRED:
     case google_apis::HTTP_PRECONDITION:
     case google_apis::GDATA_PARSE_ERROR:
     case google_apis::GDATA_OTHER_ERROR:
       return SYNC_STATUS_FAILED;
 
     case google_apis::GDATA_NO_SPACE:
       return SYNC_FILE_ERROR_NO_SPACE;
   }
-  NOTREACHED();
+
+  // There's a case where DriveService layer returns GDataErrorCode==-1
+  // when network is unavailable. (http://crbug.com/223042)
+  // TODO(kinuko,nhiroki): We should identify from where this undefined error
+  // code is coming.
+  if (error == -1)
+    return SYNC_STATUS_NETWORK_ERROR;
+
+  LOG(WARNING) << "Got unexpected error: " << error;
   return SYNC_STATUS_FAILED;
 }
 
 google_apis::GDataErrorCode DriveUploadErrorToGDataErrorCode(
     google_apis::DriveUploadError error) {
   switch (error) {
     case google_apis::DRIVE_UPLOAD_OK:
        return google_apis::HTTP_SUCCESS;
     case google_apis::DRIVE_UPLOAD_ERROR_NOT_FOUND:
       return google_apis::HTTP_NOT_FOUND;
     case google_apis::DRIVE_UPLOAD_ERROR_NO_SPACE:
       return google_apis::GDATA_NO_SPACE;
     case google_apis::DRIVE_UPLOAD_ERROR_CONFLICT:
       return google_apis::HTTP_CONFLICT;
     case google_apis::DRIVE_UPLOAD_ERROR_ABORT:
       return google_apis::GDATA_OTHER_ERROR;
   }
   NOTREACHED();
   return google_apis::GDATA_OTHER_ERROR;
 }
 
 }  // namespace sync_file_system