remove AXMediaSliderHelp(Unused).

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 57 matching lines @@
         AXMediaHideClosedCaptionsButtonHelp,
         AXMediaMuteButton,
         AXMediaMuteButtonHelp,
         AXMediaPauseButton,
         AXMediaPauseButtonHelp,
         AXMediaPlayButton,
         AXMediaPlayButtonHelp,
         AXMediaShowClosedCaptionsButton,
         AXMediaShowClosedCaptionsButtonHelp,
         AXMediaSlider, // Deprecated.
-        AXMediaSliderHelp,
         AXMediaSliderThumb, // Deprecated.
         AXMediaSliderThumbHelp, // Deprecated.
         AXMediaStatusDisplay,
         AXMediaStatusDisplayHelp,
         AXMediaTimeRemainingDisplay,
         AXMediaTimeRemainingDisplayHelp,
         AXMediaUnMuteButton,
         AXMediaUnMuteButtonHelp,
         AXMediaVideoElement,
         AXMediaVideoElementHelp,
@@ skipping 78 matching lines @@
         ValidationValueMissingForRadio,
         ValidationValueMissingForSelect,
         WeekFormatTemplate,
         WeekNumberLabel,
     };
 };
 
 } // namespace blink
 
 #endif