[ObjC ARC] Converts ios/chrome/browser/ui/dialogs:dialogs_internal to ARC.

ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm

Index: ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm
diff --git a/ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm b/ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm
index b3f75621b29b66c16dae57e03b6af6d995b45bc8..0ffb4d3ce4acb533e7db91bacf9f8fc462584836 100644
--- a/ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm
+++ b/ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.mm
@@ -4,7 +4,6 @@
 
 #import "ios/chrome/browser/ui/dialogs/nsurl_protection_space_util.h"
 
-#import "base/mac/scoped_nsobject.h"
 #include "base/numerics/safe_conversions.h"
 #include "base/strings/sys_string_conversions.h"
 #include "components/strings/grit/components_strings.h"
@@ -13,6 +12,10 @@
 #include "url/gurl.h"
 #include "url/scheme_host_port.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace ios_internal {
 namespace nsurlprotectionspace_util {