A follow-up nit fix for jumplist file operations

chrome/browser/win/jumplist.cc

 // Copyright 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/win/jumplist.h"
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/command_line.h"
 #include "base/files/file_util.h"
@@ skipping 233 matching lines @@
     DELETE_DEST_FAILED = 1 << 0,
     MOVE_FAILED = 1 << 1,
     DELETE_SRC_FAILED = 1 << 2,
     CREATE_SRC_FAILED = 1 << 3,
     // This value is beyond the sum of all bit fields above and
     // should remain last (shifted by one more than the last value)
     END = 1 << 4
   };
 
   // This variable records the status of three folder operations.
-  int folder_operation_status = FolderOperationResult::SUCCESS;

[chengx, 2016/12/15 19:51:54]

grt@
nit: always use an unsigned type to hold a bitfield -- uint32_t would be good
here

+  uint32_t folder_operation_status = FolderOperationResult::SUCCESS;
 
-  if (base::PathExists(icon_dir_old) && !base::DeleteFile(icon_dir_old, true)) {

[chengx, 2016/12/15 19:51:54]

grt@
base::PathExists is unnecessary -- DeleteFile returns true if the item didn't
exist (and is documented as such).

+  if (!base::DeleteFile(icon_dir_old, true)) {
     folder_operation_status |= FolderOperationResult::DELETE_DEST_FAILED;
     // If deletion of |icon_dir_old| fails, do not move |icon_dir| to
     // |icon_dir_old|, instead, delete |icon_dir| directly to avoid bloating
     // |icon_dir_old| by moving more things to it.
     if (!base::DeleteFile(icon_dir, true))
       folder_operation_status |= FolderOperationResult::DELETE_SRC_FAILED;
   } else if (!base::Move(icon_dir, icon_dir_old)) {
     folder_operation_status |= FolderOperationResult::MOVE_FAILED;
     // If Move() fails, delete |icon_dir| to avoid file accumulation in this
     // directory, which can eventually lead the folder to be huge.
@@ skipping 341 matching lines @@
 void JumpList::TopSitesLoaded(history::TopSites* top_sites) {
 }
 
 void JumpList::TopSitesChanged(history::TopSites* top_sites,
                                ChangeReason change_reason) {
   top_sites->GetMostVisitedURLs(
       base::Bind(&JumpList::OnMostVisitedURLsAvailable,
                  weak_ptr_factory_.GetWeakPtr()),
       false);
 }