aura: Let NativeThemeBase paint ArrowButtons for aura.

ui/base/native_theme/native_theme_aura.cc

 // 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.
 
 #include "ui/base/native_theme/native_theme_aura.h"
 
 #include "base/logging.h"
 #include "grit/ui_resources.h"
 #include "ui/base/layout.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 209 matching lines @@
       gfx::ImageSkia* center = rb.GetImageSkiaNamed(
           IDR_SCROLL_BASE_HORIZONTAL_CENTER_H);
       DrawTiledImage(canvas, *center,
                      0, 0, 1.0, 1.0,
                      rect.x() + center_offset, rect.y(),
                      center_width, center->height());
     }
   }
 }
 
-void NativeThemeAura::PaintArrowButton(SkCanvas* canvas,
-                                       const gfx::Rect& rect,
-                                       Part part,
-                                       State state) const {
-  // TODO(jamescook): Should this paint something?  We used to DCHECK() here
-  // that the rect was empty, but that was failing on about: UI pages.
-}
-
 void NativeThemeAura::PaintScrollbarThumb(SkCanvas* canvas,
                                           Part part,
                                           State state,
                                           const gfx::Rect& rect) const {
   ui::ResourceBundle& rb = ui::ResourceBundle::GetSharedInstance();
   if (part == kScrollbarVerticalThumb) {
     int top_resource_id =
         state == kHovered ? IDR_SCROLL_THUMB_VERTICAL_TOP_H :
         state == kPressed ? IDR_SCROLL_THUMB_VERTICAL_TOP_P :
         IDR_SCROLL_THUMB_VERTICAL_TOP;
@@ skipping 53 matching lines @@
       DrawTiledImage(canvas, *center,
                      0, 0, 1.0, 1.0,
                      rect.x() + left->width(), rect.y(),
                      rect.width() - left->width() - right->width(),
                      center->height());
     }
   }
 }
 
 }  // namespace ui