[ObjC ARC] Converts ios/chrome/test/earl_grey:ios_chrome_device_check_egtests to ARC.

ios/chrome/test/earl_grey/device_check_egtest.mm

Index: ios/chrome/test/earl_grey/device_check_egtest.mm
diff --git a/ios/chrome/test/earl_grey/device_check_egtest.mm b/ios/chrome/test/earl_grey/device_check_egtest.mm
index 91a0428dd3d54f99e6744ee330be95aa2c38b775..913790e6f1279dbe4139eb3d811f1d77c01fc80c 100644
--- a/ios/chrome/test/earl_grey/device_check_egtest.mm
+++ b/ios/chrome/test/earl_grey/device_check_egtest.mm
@@ -9,6 +9,10 @@
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 using chrome_test_util::WebViewContainingText;
 
 // Test suite to verify Internet connectivity.