Use simplify operator< implementations in tools/

tools/gn/location.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/location.h"
 
+#include <tuple>
+
 #include "base/logging.h"
 #include "base/strings/string_number_conversions.h"
 #include "tools/gn/input_file.h"
 
 Location::Location()
     : file_(nullptr),
       line_number_(-1),
       char_offset_(-1) {
 }
 
@@ skipping 12 matching lines @@
          other.line_number_ == line_number_ &&
          other.char_offset_ == char_offset_;
 }
 
 bool Location::operator!=(const Location& other) const {
   return !operator==(other);
 }
 
 bool Location::operator<(const Location& other) const {
   DCHECK(file_ == other.file_);
-  if (line_number_ != other.line_number_)
-    return line_number_ < other.line_number_;
-  return char_offset_ < other.char_offset_;
+  return std::tie(line_number_, char_offset_) <
+         std::tie(other.line_number_, other.char_offset_);
 }
 
 std::string Location::Describe(bool include_char_offset) const {
   if (!file_)
     return std::string();
 
   std::string ret;
   if (file_->friendly_name().empty())
     ret = file_->name().value();
   else
@@ skipping 16 matching lines @@
       end_(end) {
   DCHECK(begin_.file() == end_.file());
 }
 
 LocationRange LocationRange::Union(const LocationRange& other) const {
   DCHECK(begin_.file() == other.begin_.file());
   return LocationRange(
       begin_ < other.begin_ ? begin_ : other.begin_,
       end_ < other.end_ ? other.end_ : end_);
 }