Revert of [ObjC ARC] Converts ios/chrome/browser/ui:ui to ARC.

ios/chrome/browser/ui/show_privacy_settings_util.mm

Index: ios/chrome/browser/ui/show_privacy_settings_util.mm
diff --git a/ios/chrome/browser/ui/show_privacy_settings_util.mm b/ios/chrome/browser/ui/show_privacy_settings_util.mm
index 8b6898344dfd4266d24bc3abf79a4b9cfb3421ef..1555ab1ea27f3d780db052485d17c07b2d24688b 100644
--- a/ios/chrome/browser/ui/show_privacy_settings_util.mm
+++ b/ios/chrome/browser/ui/show_privacy_settings_util.mm
@@ -4,17 +4,15 @@
 
 #import "ios/chrome/browser/ui/show_privacy_settings_util.h"
 
+#import "base/mac/scoped_nsobject.h"
 #import "ios/chrome/browser/ui/commands/UIKit+ChromeExecuteCommand.h"
 #import "ios/chrome/browser/ui/commands/generic_chrome_command.h"
 #include "ios/chrome/browser/ui/commands/ios_command_ids.h"
 
-#if !defined(__has_feature) || !__has_feature(objc_arc)
-#error "This file requires ARC support."
-#endif
-
 void ShowClearBrowsingData() {
-  GenericChromeCommand* command = [[GenericChromeCommand alloc]
-      initWithTag:IDC_SHOW_CLEAR_BROWSING_DATA_SETTINGS];
+  base::scoped_nsobject<GenericChromeCommand> command(
+      [[GenericChromeCommand alloc]
+          initWithTag:IDC_SHOW_CLEAR_BROWSING_DATA_SETTINGS]);
   UIWindow* main_window = [[UIApplication sharedApplication] keyWindow];
   [main_window chromeExecuteCommand:command];
 }