[ObjC ARC] Converts ios/chrome/browser/ui/print:eg_tests to ARC.

ios/chrome/browser/ui/print/print_controller_egtest.mm

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #import <EarlGrey/EarlGrey.h>
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
 
 #import "ios/chrome/browser/ui/uikit_ui_util.h"
 #include "ios/chrome/grit/ios_strings.h"
 #include "ios/chrome/test/app/navigation_test_util.h"
 #import "ios/chrome/test/earl_grey/chrome_earl_grey_ui.h"
 #import "ios/chrome/test/earl_grey/chrome_matchers.h"
 #import "ios/chrome/test/earl_grey/chrome_test_case.h"
 #import "ios/web/public/test/http_server.h"
 #import "ios/web/public/test/http_server_util.h"
 #include "ui/base/l10n/l10n_util_mac.h"
 #include "url/gurl.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // URL which leads to a PDF file.
 const char kPDFURL[] = "http://ios/testing/data/http_server_files/testpage.pdf";
 
 // A test HTML URL.
 const char kHTMLURL[] = "http://test";
 }  // namespace
 
 // Print test cases. These are Earl Grey integration tests.
 // They test printing a normal page and a pdf.
@@ skipping 43 matching lines @@
   [[EarlGrey selectElementWithMatcher:printButton] performAction:grey_tap()];
 
   id<GREYMatcher> printerOptionButton = grey_allOf(
       grey_accessibilityLabel(@"Printer Options"),
       grey_not(grey_accessibilityTrait(UIAccessibilityTraitHeader)), nil);
   [[EarlGrey selectElementWithMatcher:printerOptionButton]
       assertWithMatcher:grey_sufficientlyVisible()];
 }
 
 @end