drive: Stop returning FilePath from GetResourceEntryById

chrome/browser/chromeos/drive/file_system/create_directory_operation.cc

 // Copyright (c) 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/drive/file_system/create_directory_operation.h"
 
 #include "chrome/browser/chromeos/drive/drive.pb.h"
 #include "chrome/browser/chromeos/drive/file_system/operation_observer.h"
 #include "chrome/browser/chromeos/drive/file_system_util.h"
 #include "chrome/browser/chromeos/drive/job_scheduler.h"
@@ skipping 87 matching lines @@
 
   std::string resource_id = util::kDriveGrandRootSpecialResourceId;
   for (size_t i = 1; i < components.size(); ++i) {
     std::string child_resource_id =
         metadata->GetChildResourceId(resource_id, components[i]);
     if (child_resource_id.empty())
       break;
     resource_id = child_resource_id;
   }
 
-  FileError error = metadata->GetResourceEntryById(resource_id, NULL, entry);
+  FileError error = metadata->GetResourceEntryById(resource_id, entry);
   DCHECK_EQ(FILE_ERROR_OK, error);
 
   if (!entry->file_info().is_directory())
     return base::FilePath();
 
   return metadata->GetFilePath(resource_id);
 }
 
 void CreateDirectoryOperation::CreateDirectoryAfterGetExistingDeepestDirectory(
     const base::FilePath& directory_path,
@@ skipping 110 matching lines @@
     callback.Run(FILE_ERROR_OK);
     return;
   }
 
   // Create descendent directories.
   CreateDirectoryRecursively(resource_id, remaining_path, callback);
 }
 
 }  // namespace file_system
 }  // namespace drive