Replace NULL with nullptr in all C++ files.

webrtc/examples/peerconnection/server/data_socket.cc

Index: webrtc/examples/peerconnection/server/data_socket.cc
diff --git a/webrtc/examples/peerconnection/server/data_socket.cc b/webrtc/examples/peerconnection/server/data_socket.cc
index 60e40a68e6a515d006acaceea9f2aae327576604..b13413ab3d4a7791f31a74ef3f234d5ef4260350 100644
--- a/webrtc/examples/peerconnection/server/data_socket.cc
+++ b/webrtc/examples/peerconnection/server/data_socket.cc
@@ -195,7 +195,7 @@ bool DataSocket::ParseMethodAndPath(const char* begin, size_t len) {
     { "OPTIONS", 7, OPTIONS },
   };
 
-  const char* path = NULL;
+  const char* path = nullptr;
   for (size_t i = 0; i < ARRAYSIZE(supported_methods); ++i) {
     if (len > supported_methods[i].method_name_len &&
         isspace(begin[supported_methods[i].method_name_len]) &&
@@ -244,7 +244,7 @@ bool DataSocket::ParseContentLengthAndType(const char* headers, size_t length) {
         while (headers[0] == ' ')
           ++headers;
         const char* type_end = strstr(headers, "\r\n");
-        if (type_end == NULL)
+        if (type_end == nullptr)
           type_end = end;
         content_type_.assign(headers, type_end);
       }
@@ -287,7 +287,7 @@ DataSocket* ListeningSocket::Accept() const {
   NativeSocket client =
       accept(socket_, reinterpret_cast<sockaddr*>(&addr), &size);
   if (client == INVALID_SOCKET)
-    return NULL;
+    return nullptr;
 
   return new DataSocket(client);
 }