Switch to standard integer types in tools/.

tools/gn/string_utils.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/string_utils.h"
 
+#include <stddef.h>
+
 #include "tools/gn/err.h"
 #include "tools/gn/input_file.h"
 #include "tools/gn/parser.h"
 #include "tools/gn/scope.h"
 #include "tools/gn/token.h"
 #include "tools/gn/tokenizer.h"
 #include "tools/gn/value.h"
 
 namespace {
 
@@ skipping 218 matching lines @@
     } else if (input[i] == '$') {
       if (!AppendStringInterpolation(scope, literal, input, size, &i,
                                      &output, err))
         return false;
     } else {
       output.push_back(input[i]);
     }
   }
   return true;
 }