Add JSON-specific escaping, which has different rules from JS escaping.

base/string_util.h

 // Copyright (c) 2006-2008 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.
 //
 // This file defines utility functions for working with strings.
 
 #ifndef BASE_STRING_UTIL_H_
 #define BASE_STRING_UTIL_H_
 
 #include <stdarg.h>   // va_list
@@ skipping 577 matching lines @@
 
 // Returns a hex string representation of a binary buffer.
 // The returned hex string will be in upper case.
 // This function does not check if |size| is within reasonable limits since
 // it's written with trusted data in mind.
 // If you suspect that the data you want to format might be large,
 // the absolute max size for |size| should be is
 //   std::numeric_limits<size_t>::max() / 2
 std::string HexEncode(const void* bytes, size_t size);
 
+// Hack to convert any char-like type to its unsigned counterpart.
+// For example, it will convert char, signed char and unsigned char to unsigned
+// char.
+template<typename T>
+struct ToUnsigned {
+  typedef T Unsigned;
+};
+
+template<>
+struct ToUnsigned<char> {
+  typedef unsigned char Unsigned;
+};
+template<>
+struct ToUnsigned<signed char> {
+  typedef unsigned char Unsigned;
+};
+template<>
+struct ToUnsigned<wchar_t> {
+#if defined(WCHAR_T_IS_UTF16)
+  typedef unsigned short Unsigned;
+#elif defined(WCHAR_T_IS_UTF32)
+  typedef uint32 Unsigned;
+#endif
+};
+template<>
+struct ToUnsigned<short> {
+  typedef unsigned short Unsigned;
+};
 
 #endif  // BASE_STRING_UTIL_H_