Remove base::Value::CreateNullValue

chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc

Index: chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc
diff --git a/chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc b/chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc
index fc01881bd0d62d559decc58a74e67d0b8c95d2e7..f3319f57c04ae9a43bc7a20d8bbdf909f881e594 100644
--- a/chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc
+++ b/chrome/browser/ui/webui/chromeos/first_run/first_run_handler.cc
@@ -5,6 +5,7 @@
 #include "chrome/browser/ui/webui/chromeos/first_run/first_run_handler.h"
 
 #include "base/bind.h"
+#include "base/memory/ptr_util.h"
 #include "base/values.h"
 #include "content/public/browser/web_ui.h"
 
@@ -50,7 +51,7 @@ void FirstRunHandler::ShowStepPointingTo(const std::string& name,
                                          int x,
                                          int y,
                                          int offset) {
-  std::unique_ptr<base::Value> null = base::Value::CreateNullValue();
+  auto null = base::MakeUnique<base::Value>();
   base::ListValue point_with_offset;
   point_with_offset.AppendInteger(x);
   point_with_offset.AppendInteger(y);