[ObjC ARC] Converts ios/chrome/browser/ui/bookmarks:bookmarks_arc to ARC.

ios/chrome/browser/ui/bookmarks/bookmark_extended_button.mm

 // Copyright 2014 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/browser/ui/bookmarks/bookmark_extended_button.h"
 
 #include "base/logging.h"
 
+#if !defined(__has_feature) || !__has_feature(objc_arc)
+#error "This file requires ARC support."
+#endif
+
 namespace {
 // Apple's guidelines indicate that buttons should have a minimum touch area of
 // 44pt x 44pt.
 CGFloat kMinimumLength = 44;
 }  // namespace
 
 @interface BookmarkExtendedButton ()
 @property(nonatomic, assign) BOOL doesExtendEdges;
 @end
 
@@ skipping 46 matching lines @@
 
 - (CGRect)accessibilityFrame {
   CGRect touchArea = [self touchArea];
   CGRect touchAreaInWindowCoordinates = [self convertRect:touchArea toView:nil];
   CGRect touchAreaInScreenCoordinates =
       [self.window convertRect:touchAreaInWindowCoordinates toWindow:nil];
   return touchAreaInScreenCoordinates;
 }
 
 @end