AX: Make picker indicator elements focusable if accessibility is enabled.

public/platform/WebLocalizedString.h

 /*
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 67 matching lines @@
         AXMediaTimeRemainingDisplayHelp,
         AXMediaUnMuteButton,
         AXMediaUnMuteButtonHelp,
         AXMediaVideoElement,
         AXMediaVideoElementHelp,
         AXMillisecondFieldText,
         AXMinuteFieldText,
         AXMonthFieldText,
         AXRadioButtonActionVerb,
         AXSecondFieldText,
+        AXShowPickerButton,
         AXTextFieldActionVerb,
         AXUncheckedCheckBoxActionVerb,
         AXWebAreaText, // Deprecated.
         AXWeekOfYearFieldText,
         AXYearFieldText,
         BlockedPluginText,
         CalendarClear,
         CalendarToday,
         DateFormatDayInMonthLabel,
         DateFormatMonthLabel,
@@ skipping 61 matching lines @@
         ValidationValueMissingForRadio,
         ValidationValueMissingForSelect,
         WeekFormatTemplate,
         WeekNumberLabel,
     };
 };
 
 } // namespace blink
 
 #endif