Fix scrollbar buttons on ChromeOS.

ui/native_theme/native_theme_base.h

Index: ui/native_theme/native_theme_base.h
diff --git a/ui/native_theme/native_theme_base.h b/ui/native_theme/native_theme_base.h
index 74525ce67fbf4dfcbbc7d2cc3356ae6d797178e2..e35ad5a682e267ffe47c77764b08d8f79bf6ff6d 100644
--- a/ui/native_theme/native_theme_base.h
+++ b/ui/native_theme/native_theme_base.h
@@ -151,11 +151,6 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
   // crbug.com/530746 is resolved.
   virtual void AdjustCheckboxRadioRectForPadding(SkRect* rect) const;
 
-  void set_scrollbar_button_length(unsigned int length) {
-    scrollbar_button_length_ = length;
-  }
-  int scrollbar_button_length() const { return scrollbar_button_length_; }
-
   SkColor SaturateAndBrighten(SkScalar* hsv,
                               SkScalar saturate_amount,
                               SkScalar brighten_amount) const;
@@ -203,9 +198,6 @@ class NATIVE_THEME_EXPORT NativeThemeBase : public NativeTheme {
 
   unsigned int scrollbar_width_;
 
-  // The length of the arrow buttons, 0 means no buttons are drawn.
-  unsigned int scrollbar_button_length_;
-
   DISALLOW_COPY_AND_ASSIGN(NativeThemeBase);
 };