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

ios/chrome/test/earl_grey/chrome_actions.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 "ios/chrome/test/earl_grey/chrome_actions.h"
 
 #import "base/mac/foundation_util.h"
 #import "ios/chrome/browser/ui/collection_view/cells/collection_view_switch_item.h"
 #import "ios/chrome/test/app/chrome_test_util.h"
 #import "ios/web/public/test/earl_grey/web_view_actions.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace chrome_test_util {
 
 id<GREYAction> longPressElementForContextMenu(const std::string& element_id,
                                               bool triggers_context_menu) {
   return webViewLongPressElementForContextMenu(
       chrome_test_util::GetCurrentWebState(), element_id,
       triggers_context_menu);
 }
 
 id<GREYAction> turnCollectionViewSwitchOn(BOOL on) {
@@ skipping 13 matching lines @@
           if (switchView.on ^ on) {
             id<GREYAction> longPressAction = [GREYActions
                 actionForLongPressWithDuration:kGREYLongPressDefaultDuration];
             return [longPressAction perform:switchView error:errorOrNil];
           }
           return YES;
         }];
 }
 
 }  // namespace chrome_test_util