Replace NULL with nullptr in all C++ files.

webrtc/base/socketadapters.cc

Index: webrtc/base/socketadapters.cc
diff --git a/webrtc/base/socketadapters.cc b/webrtc/base/socketadapters.cc
index f6029ce964545695e99c93288720922e7ec0338a..a51b1f98b87651f377e0af3ce71ebd6b8bcae5a9 100644
--- a/webrtc/base/socketadapters.cc
+++ b/webrtc/base/socketadapters.cc
@@ -281,7 +281,7 @@ int AsyncHttpsProxySocket::Close() {
   state_ = PS_ERROR;
   dest_.Clear();
   delete context_;
-  context_ = NULL;
+  context_ = nullptr;
   return BufferedReadAdapter::Close();
 }
 
@@ -889,8 +889,8 @@ int LoggingSocketAdapter::RecvFrom(void* pv,
 }
 
 int LoggingSocketAdapter::Close() {
-  LogMultiline(level_, label_.c_str(), false, NULL, 0, hex_mode_, &lms_);
-  LogMultiline(level_, label_.c_str(), true, NULL, 0, hex_mode_, &lms_);
+  LogMultiline(level_, label_.c_str(), false, nullptr, 0, hex_mode_, &lms_);
+  LogMultiline(level_, label_.c_str(), true, nullptr, 0, hex_mode_, &lms_);
   LOG_V(level_) << label_ << " Closed locally";
   return socket_->Close();
 }
@@ -901,8 +901,8 @@ void LoggingSocketAdapter::OnConnectEvent(AsyncSocket * socket) {
 }
 
 void LoggingSocketAdapter::OnCloseEvent(AsyncSocket * socket, int err) {
-  LogMultiline(level_, label_.c_str(), false, NULL, 0, hex_mode_, &lms_);
-  LogMultiline(level_, label_.c_str(), true, NULL, 0, hex_mode_, &lms_);
+  LogMultiline(level_, label_.c_str(), false, nullptr, 0, hex_mode_, &lms_);
+  LogMultiline(level_, label_.c_str(), true, nullptr, 0, hex_mode_, &lms_);
   LOG_V(level_) << label_ << " Closed with error: " << err;
   AsyncSocketAdapter::OnCloseEvent(socket, err);
 }