Overlay scrollbars flush with window edge

ui/native_theme/native_theme_base.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_NATIVE_THEME_NATIVE_THEME_BASE_H_
 #define UI_NATIVE_THEME_NATIVE_THEME_BASE_H_
 
 #include <memory>
 
 #include "base/compiler_specific.h"
@@ skipping 42 matching lines @@
       Part part,
       State state,
       const ScrollbarTrackExtraParams& extra_params,
       const gfx::Rect& rect) const;
   // Draw the scrollbar thumb over the track.
   virtual void PaintScrollbarThumb(
       cc::PaintCanvas* canvas,
       Part part,
       State state,
       const gfx::Rect& rect,
-      NativeTheme::ScrollbarOverlayColorTheme theme) const;
+      const NativeTheme::ScrollbarThumbExtraParams& params) const;
 
   virtual void PaintScrollbarCorner(cc::PaintCanvas* canvas,
                                     State state,
                                     const gfx::Rect& rect) const;
 
   virtual void PaintCheckbox(cc::PaintCanvas* canvas,
                              State state,
                              const gfx::Rect& rect,
                              const ButtonExtraParams& button) const;
 
@@ skipping 122 matching lines @@
 
   // The length of the arrow buttons, 0 means no buttons are drawn.
   int scrollbar_button_length_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeBase);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_BASE_H_