a11y: add a11y title for bookmark chevron / "off the side button"

chrome/browser/ui/cocoa/bookmarks/bookmark_button_cell.mm

 // Copyright (c) 2011 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 "chrome/browser/ui/cocoa/bookmarks/bookmark_button_cell.h"
 
 #include "base/logging.h"
 #include "base/strings/sys_string_conversions.h"
 #include "chrome/browser/ui/cocoa/bookmarks/bookmark_bar_constants.h"
 #import "chrome/browser/ui/cocoa/bookmarks/bookmark_button.h"
@@ skipping 22 matching lines @@
 
 const int kIconTextSpacer = 4;
 const int kTextRightPadding = 4;
 const int kIconLeftPadding = 4;
 
 const int kDefaultFontSize = 12;
 
 };  // namespace
 
 @interface OffTheSideButtonCell : BookmarkButtonCell
+
+- (NSString*)accessibilityTitle;
+
 @end
 @implementation OffTheSideButtonCell
 
 - (BOOL)isOffTheSideButtonCell {
   return YES;
 }
 
+- (NSString*)accessibilityTitle {
+  return l10n_util::GetNSString(IDS_ACCNAME_BOOKMARKS_CHEVRON);
+}
+
 @end
 
 @interface BookmarkButtonCell(Private)
 // Returns YES if the cell is the offTheSide button cell.
 - (BOOL)isOffTheSideButtonCell;
 - (void)configureBookmarkButtonCell;
 - (void)applyTextColor;
 // Returns the title the button cell displays. Note that a button cell can
 // have a title string assigned but it won't be visible if its image position
 // is NSImageOnly.
@@ skipping 383 matching lines @@
   const CGFloat kLineWidth = [controlView cr_lineWidth];
   if ([self isMaterialDesignButtonType] && ![self isFolderButtonCell] &&
       kLineWidth < 1) {
     return -kLineWidth;
   }
   return 0.0;
 }
 
 
 @end