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

webrtc/api/jsepicecandidate.h

 /*
  *  Copyright 2012 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 13 matching lines @@
 
 namespace webrtc {
 
 // Implementation of IceCandidateInterface.
 class JsepIceCandidate : public IceCandidateInterface {
  public:
   JsepIceCandidate(const std::string& sdp_mid, int sdp_mline_index);
   JsepIceCandidate(const std::string& sdp_mid, int sdp_mline_index,
                    const cricket::Candidate& candidate);
   ~JsepIceCandidate();
-  // |err| may be NULL.
+  // |err| may be null.
   bool Initialize(const std::string& sdp, SdpParseError* err);
   void SetCandidate(const cricket::Candidate& candidate) {
     candidate_ = candidate;
   }
 
   virtual std::string sdp_mid() const { return sdp_mid_; }
   virtual int sdp_mline_index() const { return sdp_mline_index_; }
   virtual const cricket::Candidate& candidate() const {
     return candidate_;
   }
@@ skipping 39 matching lines @@
 
  private:
   std::vector<JsepIceCandidate*> candidates_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(JsepCandidateCollection);
 };
 
 }  // namespace webrtc
 
 #endif  // WEBRTC_API_JSEPICECANDIDATE_H_