replace NULL->nullptr in src/remoting.

remoting/host/host_event_logger_win.cc

Index: remoting/host/host_event_logger_win.cc
diff --git a/remoting/host/host_event_logger_win.cc b/remoting/host/host_event_logger_win.cc
index 374cddb7e892f2ede73cdadb1ae5f768d24ebfe6..050d7256b07b4393a3cb87ae536becd418275f85 100644
--- a/remoting/host/host_event_logger_win.cc
+++ b/remoting/host/host_event_logger_win.cc
@@ -59,10 +59,10 @@ class HostEventLoggerWin : public HostEventLogger, public HostStatusObserver {
 HostEventLoggerWin::HostEventLoggerWin(base::WeakPtr<HostStatusMonitor> monitor,
                                        const std::string& application_name)
     : monitor_(monitor),
-      event_log_(NULL) {
+      event_log_(nullptr) {
   event_log_ = RegisterEventSourceW(
-      NULL, base::UTF8ToUTF16(application_name).c_str());
-  if (event_log_ != NULL) {
+      nullptr, base::UTF8ToUTF16(application_name).c_str());
+  if (event_log_ != nullptr) {
     monitor_->AddStatusObserver(this);
   } else {
     PLOG(ERROR) << "Failed to register the event source: " << application_name;
@@ -70,7 +70,7 @@ HostEventLoggerWin::HostEventLoggerWin(base::WeakPtr<HostStatusMonitor> monitor,
 }
 
 HostEventLoggerWin::~HostEventLoggerWin() {
-  if (event_log_ != NULL) {
+  if (event_log_ != nullptr) {
     if (monitor_)
       monitor_->RemoveStatusObserver(this);
     DeregisterEventSource(event_log_);
@@ -113,7 +113,7 @@ void HostEventLoggerWin::OnStart(const std::string& xmpp_login) {
 void HostEventLoggerWin::Log(WORD type,
                              DWORD event_id,
                              const std::vector<std::string>& strings) {
-  if (event_log_ == NULL)
+  if (event_log_ == nullptr)
     return;
 
   // ReportEventW() takes an array of raw string pointers. They should stay
@@ -129,11 +129,11 @@ void HostEventLoggerWin::Log(WORD type,
                     type,
                     HOST_CATEGORY,
                     event_id,
-                    NULL,
+                    nullptr,
                     static_cast<WORD>(raw_strings.size()),
                     0,
                     &raw_strings[0],
-                    NULL)) {
+                    nullptr)) {
     PLOG(ERROR) << "Failed to write an event to the event log";
   }
 }