Replace NULL with nullptr or null in webrtc/base/.

webrtc/base/stringutils.h

 /*
  *  Copyright 2004 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
@@ skipping 118 matching lines @@
   // STL string type
   //typedef XXX string;
   // Null-terminated string
   //inline static const CTYPE* empty_str();
 };
 
 ///////////////////////////////////////////////////////////////////////////////
 // String utilities which work with char or wchar_t
 ///////////////////////////////////////////////////////////////////////////////
 
-template<class CTYPE>
-inline const CTYPE* nonnull(const CTYPE* str, const CTYPE* def_str = NULL) {
+template <class CTYPE>
+inline const CTYPE* nonnull(const CTYPE* str, const CTYPE* def_str = nullptr) {
   return str ? str : (def_str ? def_str : Traits<CTYPE>::empty_str());
 }
 
 template<class CTYPE>
 const CTYPE* strchr(const CTYPE* str, const CTYPE* chs) {
   for (size_t i=0; str[i]; ++i) {
     for (size_t j=0; chs[j]; ++j) {
       if (str[i] == chs[j]) {
         return str + i;
       }
@@ skipping 156 matching lines @@
 
 // True iff s1 ends with s2.
 bool ends_with(const char *s1, const char *s2);
 
 // Remove leading and trailing whitespaces.
 std::string string_trim(const std::string& s);
 
 }  // namespace rtc
 
 #endif // WEBRTC_BASE_STRINGUTILS_H__