Handled nullptr argument in WaitForExit() and WaitForExitWithTimeout() methods.

base/process/process_posix.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "base/process/process.h"
 
 #include <sys/resource.h>
 #include <sys/wait.h>
 
 #include "base/files/scoped_file.h"
@@ skipping 175 matching lines @@
 #else
     // Currently on Linux we can't handle non child processes.
     NOTIMPLEMENTED();
 #endif  // OS_MACOSX
   }
 
   int status;
   if (!WaitpidWithTimeout(handle, &status, timeout))
     return false;
   if (WIFSIGNALED(status)) {
-    *exit_code = -1;
+    if (exit_code)
+      *exit_code = -1;
     return true;
   }
   if (WIFEXITED(status)) {
-    *exit_code = WEXITSTATUS(status);
+    if (exit_code)
+      *exit_code = WEXITSTATUS(status);
     return true;
   }
   return false;
 }
 #endif  // !defined(OS_NACL_NONSFI)
 
 }  // namespace
 
 namespace base {
 
@@ skipping 157 matching lines @@
   return false;
 }
 #endif  // !defined(OS_LINUX)
 
 int Process::GetPriority() const {
   DCHECK(IsValid());
   return getpriority(PRIO_PROCESS, process_);
 }
 
 }  // namespace base