Draw nicer arrows when the scrollbar buttons are not square.

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 152 matching lines @@
   // Paints the arrow used on the scrollbar and spinner.
   void PaintArrow(SkCanvas* canvas,
                   const gfx::Rect& rect,
                   Part direction,
                   SkColor color) const;
 
   // Returns the color used to draw the arrow.
   SkColor GetArrowColor(State state) const;
 
  private:
-  FRIEND_TEST_ALL_PREFIXES(NativeThemeAuraTest, VerticalArrows);
-  FRIEND_TEST_ALL_PREFIXES(NativeThemeAuraTest, HorizontalArrows);
+  friend class NativeThemeAuraTest;
 
   SkPath PathForArrow(const gfx::Rect& rect, Part direction) const;
+  gfx::Rect BoundingRectForArrow(const gfx::Rect& rect) const;
 
   void DrawVertLine(SkCanvas* canvas,
                     int x,
                     int y1,
                     int y2,
                     const SkPaint& paint) const;
   void DrawHorizLine(SkCanvas* canvas,
                      int x1,
                      int x2,
                      int y,
@@ skipping 18 matching lines @@
 
   // The length of the arrow buttons, 0 means no buttons are drawn.
   unsigned int scrollbar_button_length_;
 
   DISALLOW_COPY_AND_ASSIGN(NativeThemeBase);
 };
 
 }  // namespace ui
 
 #endif  // UI_NATIVE_THEME_NATIVE_THEME_BASE_H_