Revert 240670 "Revert 239894 "Linux Sandbox: check no threads be..."

trunk/src/sandbox/linux/services/broker_process.cc

Index: trunk/src/sandbox/linux/services/broker_process.cc
===================================================================
--- trunk/src/sandbox/linux/services/broker_process.cc	(revision 240957)
+++ trunk/src/sandbox/linux/services/broker_process.cc	(working copy)
@@ -21,6 +21,7 @@
 #include "base/pickle.h"
 #include "base/posix/eintr_wrapper.h"
 #include "base/posix/unix_domain_socket_linux.h"
+#include "base/process/process_metrics.h"
 #include "build/build_config.h"
 #include "sandbox/linux/services/linux_syscalls.h"
 
@@ -146,6 +147,7 @@
     return false;
   }
 
+  DCHECK_EQ(1, base::GetNumberOfThreads(base::GetCurrentProcessHandle()));
   int child_pid = fork();
   if (child_pid == -1) {
     close(socket_pair[0]);