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

ios/chrome/test/earl_grey/accessibility_util.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 <XCTest/XCTest.h>
 
 #include "ios/chrome/test/earl_grey/accessibility_util.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 
 // Returns whether a UIView is hidden from the screen, based on the alpha
 // and hidden properties of the UIView.
 bool ViewIsHidden(UIView* view) {
   return view.alpha == 0 || view.hidden;
 }
 
 // Returns whether a view should be accessible. A view should be accessible if
 // either it is a whitelisted type or its isAccessibilityElement property is
@@ skipping 324 matching lines @@
   GREYAssert(!inaccessibleChildrenError,
              @"The accessibility tests failed: Inaccessible children error");
   GREYAssert(!noLabels, @"The accessibility tests failed: No labels error");
   GREYAssert(!badDefaultLabel,
              @"The accessibility tests failed: Bad default labels error");
   GREYAssert(!tableViewError,
              @"The accessibility tests failed: Table view error");
 }
 
 }  // namespace chrome_test_util