Convert //tools to use std::unique_ptr

tools/gn/xml_element_writer.cc

 // Copyright 2016 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/xml_element_writer.h"
 
+#include "base/memory/ptr_util.h"
+
 XmlAttributes::XmlAttributes() {}
 
 XmlAttributes::XmlAttributes(const base::StringPiece& attr_key,
                              const base::StringPiece& attr_value) {
   add(attr_key, attr_value);
 }
 
 XmlAttributes& XmlAttributes::add(const base::StringPiece& attr_key,
                                   const base::StringPiece& attr_value) {
   push_back(std::make_pair(attr_key, attr_value));
@@ skipping 29 matching lines @@
       out_ << std::string(indent_, ' ');
     out_ << "</" << tag_ << '>' << std::endl;
   }
 }
 
 void XmlElementWriter::Text(const base::StringPiece& content) {
   StartContent(false);
   out_ << content;
 }
 
-scoped_ptr<XmlElementWriter> XmlElementWriter::SubElement(
+std::unique_ptr<XmlElementWriter> XmlElementWriter::SubElement(
     const std::string& tag) {
   return SubElement(tag, XmlAttributes());
 }
 
-scoped_ptr<XmlElementWriter> XmlElementWriter::SubElement(
+std::unique_ptr<XmlElementWriter> XmlElementWriter::SubElement(
     const std::string& tag,
     const XmlAttributes& attributes) {
   StartContent(true);
-  return make_scoped_ptr(
+  return base::WrapUnique(
       new XmlElementWriter(out_, tag, attributes, indent_ + 2));
 }
 
 std::ostream& XmlElementWriter::StartContent(bool start_new_line) {
   if (!opening_tag_finished_) {
     out_ << '>';
     opening_tag_finished_ = true;
 
     if (start_new_line && one_line_) {
       out_ << std::endl;
       one_line_ = false;
     }
   }
 
   return out_;
 }