aura: Let NativeThemeBase paint ArrowButtons for aura.

ui/base/native_theme/native_theme_aura.h

 // 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.
 
 #ifndef UI_BASE_NATIVE_THEME_NATIVE_THEME_AURA_H_
 #define UI_BASE_NATIVE_THEME_NATIVE_THEME_AURA_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/base/native_theme/native_theme_base.h"
@@ skipping 12 matching lines @@
   // Overridden from NativeThemeBase:
   virtual SkColor GetSystemColor(ColorId color_id) const OVERRIDE;
   virtual void PaintMenuPopupBackground(SkCanvas* canvas,
                                         const gfx::Size& size) const OVERRIDE;
   virtual void PaintScrollbarTrack(
       SkCanvas* canvas,
       Part part,
       State state,
       const ScrollbarTrackExtraParams& extra_params,
       const gfx::Rect& rect) const OVERRIDE;
-  virtual void PaintArrowButton(SkCanvas* canvas,
-                                const gfx::Rect& rect,
-                                Part direction,
-                                State state) const OVERRIDE;
   virtual void PaintScrollbarThumb(SkCanvas* canvas,
                                    Part part,
                                    State state,
                                    const gfx::Rect& rect) const OVERRIDE;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeAura);
 };
 
 }  // namespace ui
 
 #endif  // UI_BASE_NATIVE_THEME_NATIVE_THEME_AURA_H_