webui: fix an instance of bugprone-unused-raii

It seems that this constructor call was intended to be used as a scope
guard. In order for that to happen, there has to be a variable name
here.

Bug: 1130379
Change-Id: Ibc40863e1cfe31616b18c304358274ba89ba9bf9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2420919Reviewed-by: Esmael Elmoslimany <aee@chromium.org>
Commit-Queue: George Burgess <gbiv@chromium.org>
Cr-Commit-Position: refs/heads/master@{#809405}

chrome/browser/ui/webui/settings/people_handler_unittest.cc

@@ -1240,7 +1240,7 @@ TEST(PeopleHandlerDiceUnifiedConsentTest, StoredAccountsList) {
   // Do not be in first run, so that the profiles are not created as "new
   // profiles" and automatically migrated to Dice.
   first_run::ResetCachedSentinelDataForTesting();
-  base::ScopedClosureRunner(
+  base::ScopedClosureRunner scoped_closure_runner(
       base::BindOnce(&first_run::ResetCachedSentinelDataForTesting));
   base::CommandLine::ForCurrentProcess()->AppendSwitch(switches::kNoFirstRun);
   ASSERT_FALSE(first_run::IsChromeFirstRun());