Convert //tools to use std::unique_ptr

tools/gn/build_settings.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 "tools/gn/build_settings.h"
 
 #include <utility>
 
 #include "base/files/file_util.h"
 #include "tools/gn/filesystem_utils.h"
@@ skipping 41 matching lines @@
 base::FilePath BuildSettings::GetFullPathSecondary(
     const SourceFile& file) const {
   return file.Resolve(secondary_source_path_).NormalizePathSeparatorsTo('/');
 }
 
 base::FilePath BuildSettings::GetFullPathSecondary(
     const SourceDir& dir) const {
   return dir.Resolve(secondary_source_path_).NormalizePathSeparatorsTo('/');
 }
 
-void BuildSettings::ItemDefined(scoped_ptr<Item> item) const {
+void BuildSettings::ItemDefined(std::unique_ptr<Item> item) const {
   DCHECK(item);
   if (!item_defined_callback_.is_null())
     item_defined_callback_.Run(std::move(item));
 }