Stop doing unnecessary UTF-8 to UTF-16 conversions in JSONWriter.

sync/internal_api/public/base/ordinal.h

 // Copyright (c) 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.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_BASE_ORDINAL_H_
 #define SYNC_INTERNAL_API_PUBLIC_BASE_ORDINAL_H_
 
 #include <algorithm>
 #include <cstddef>
 #include <string>
@@ skipping 242 matching lines @@
     return true;
 
   if (!IsValid() || !other.IsValid())
     return false;
 
   return Equals(other);
 }
 
 template <typename Traits>
 std::string Ordinal<Traits>::ToDebugString() const {
-  std::string debug_string;
-  base::JsonDoubleQuote(bytes_, false /* put_in_quotes */, &debug_string);
+  std::string debug_string =
+      base::EscapeBytesAsInvalidJSONString(bytes_, false /* put_in_quotes */);
   if (!is_valid_) {
     debug_string = "INVALID[" + debug_string + "]";
   }
   return debug_string;
 }
 
 template <typename Traits>
 bool Ordinal<Traits>::LessThan(const Ordinal& other) const {
   CHECK(IsValid());
   CHECK(other.IsValid());
@@ skipping 202 matching lines @@
   DCHECK_LT(midpoint, end_bytes);
 
   Ordinal<Traits> midpoint_ordinal(midpoint);
   DCHECK(midpoint_ordinal.IsValid());
   return midpoint_ordinal;
 }
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_BASE_ORDINAL_H_