Update AX role mapping for summary to AXButton on Mac

content/browser/accessibility/browser_accessibility_cocoa.mm

 // Copyright (c) 2012 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 "content/browser/accessibility/browser_accessibility_cocoa.h"
 
 #include <execinfo.h>
 #include <stddef.h>
 #include <stdint.h>
 #include <string.h>
@@ skipping 1437 matching lines @@
         IDS_AX_ROLE_CONTENT_INFO));
   case ui::AX_ROLE_DESCRIPTION_LIST:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_DESCRIPTION_LIST));
   case ui::AX_ROLE_DESCRIPTION_LIST_DETAIL:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_DEFINITION));
   case ui::AX_ROLE_DESCRIPTION_LIST_TERM:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_DESCRIPTION_TERM));
+  case ui::AX_ROLE_DISCLOSURE_TRIANGLE:
+    return base::SysUTF16ToNSString(content_client->GetLocalizedString(
+        IDS_AX_ROLE_DISCLOSURE_TRIANGLE));
   case ui::AX_ROLE_FIGURE:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_FIGURE));
   case ui::AX_ROLE_FOOTER:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_FOOTER));
   case ui::AX_ROLE_FORM:
     return base::SysUTF16ToNSString(content_client->GetLocalizedString(
         IDS_AX_ROLE_FORM));
   case ui::AX_ROLE_MAIN:
@@ skipping 1411 matching lines @@
 }
 
 - (BOOL)accessibilityNotifiesWhenDestroyed {
   // Indicate that BrowserAccessibilityCocoa will post a notification when it's
   // destroyed (see -detach). This allows VoiceOver to do some internal things
   // more efficiently.
   return YES;
 }
 
 @end