Plumbs through support for painting the scrollbarcorner

ui/native_theme/native_theme_aurawin.h

 // Copyright 2014 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_NATIVE_THEME_NATIVE_THEME_AURAWIN_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_AURAWIN_H_
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "ui/native_theme/native_theme_aura.h"
@@ skipping 24 matching lines @@
   virtual void PaintScrollbarTrack(
       SkCanvas* sk_canvas,
       Part part,
       State state,
       const ScrollbarTrackExtraParams& extra_params,
       const gfx::Rect& rect) const OVERRIDE;
   virtual void PaintScrollbarThumb(SkCanvas* sk_canvas,
                                    Part part,
                                    State state,
                                    const gfx::Rect& rect) const OVERRIDE;
+  virtual void PaintScrollbarCorner(SkCanvas* canvas,
+                                    State state,
+                                    const gfx::Rect& rect) const OVERRIDE;
 
   // Returns the NineImagePainter used to paint the specified state, creating if
   // necessary. If no image is provided for the specified state the normal state
   // images are used.
   gfx::NineImagePainter* GetOrCreatePainter(
       const int image_ids[kMaxState][9],
       State state,
       scoped_ptr<gfx::NineImagePainter> painters[kMaxState]) const;
 
   // Paints |painter| into the canvas using |rect|.
   void PaintPainter(gfx::NineImagePainter* painter,
                     SkCanvas* sk_canvas,
                     const gfx::Rect& rect) const;
 
   mutable scoped_ptr<gfx::NineImagePainter> scrollbar_track_painter_;
 
   mutable scoped_ptr<gfx::NineImagePainter>
       scrollbar_thumb_painters_[kMaxState];
 
   mutable scoped_ptr<gfx::NineImagePainter>
       scrollbar_arrow_button_painters_[kMaxState];
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeAuraWin);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_AURAWIN_H_