Convert //sandbox to use std::unique_ptr

sandbox/linux/services/credentials_unittest.cc

Index: sandbox/linux/services/credentials_unittest.cc
diff --git a/sandbox/linux/services/credentials_unittest.cc b/sandbox/linux/services/credentials_unittest.cc
index d666a0c147f5ecf144c32e5b02dfb3227ca491db..b95ba0bab273ebf4a11f165fd0dd8992b42edf72 100644
--- a/sandbox/linux/services/credentials_unittest.cc
+++ b/sandbox/linux/services/credentials_unittest.cc
@@ -15,13 +15,13 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#include <memory>
 #include <vector>
 
 #include "base/files/file_path.h"
 #include "base/files/file_util.h"
 #include "base/files/scoped_file.h"
 #include "base/logging.h"
-#include "base/memory/scoped_ptr.h"
 #include "sandbox/linux/services/proc_util.h"
 #include "sandbox/linux/services/syscall_wrappers.h"
 #include "sandbox/linux/system_headers/capability.h"
@@ -40,7 +40,7 @@ struct CapFreeDeleter {
 };
 
 // Wrapper to manage libcap2's cap_t type.
-typedef scoped_ptr<typeof(*((cap_t)0)), CapFreeDeleter> ScopedCap;
+typedef std::unique_ptr<typeof(*((cap_t)0)), CapFreeDeleter> ScopedCap;
 
 bool WorkingDirectoryIsRoot() {
   char current_dir[PATH_MAX];