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

webrtc/base/sslstreamadapter.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 193 matching lines @@
   virtual bool GetSslCipherSuite(int* cipher_suite);
 
   virtual int GetSslVersion() const = 0;
 
   // Key Exporter interface from RFC 5705
   // Arguments are:
   // label               -- the exporter label.
   //                        part of the RFC defining each exporter
   //                        usage (IN)
   // context/context_len -- a context to bind to for this connection;
-  //                        optional, can be NULL, 0 (IN)
+  //                        optional, can be null, 0 (IN)
   // use_context         -- whether to use the context value
   //                        (needed to distinguish no context from
   //                        zero-length ones).
   // result              -- where to put the computed value
   // result_len          -- the length of the computed value
   virtual bool ExportKeyingMaterial(const std::string& label,
                                     const uint8_t* context,
                                     size_t context_len,
                                     bool use_context,
                                     uint8_t* result,
@@ skipping 38 matching lines @@
 
   // If true (default), the client is required to provide a certificate during
   // handshake. If no certificate is given, handshake fails. This applies to
   // server mode only.
   bool client_auth_enabled_;
 };
 
 }  // namespace rtc
 
 #endif  // WEBRTC_BASE_SSLSTREAMADAPTER_H_