Use nine-patch resource for drawing Aura overlay scrollbar thumb.

ui/native_theme/native_theme_win.cc

Index: ui/native_theme/native_theme_win.cc
diff --git a/ui/native_theme/native_theme_win.cc b/ui/native_theme/native_theme_win.cc
index e811036b3a34af0cf0a457ddb396159a29ea4886..064f03f7b8e1c784d2359d4364d91a73e7bc5861 100644
--- a/ui/native_theme/native_theme_win.cc
+++ b/ui/native_theme/native_theme_win.cc
@@ -673,6 +673,20 @@ SkColor NativeThemeWin::GetSystemColor(ColorId color_id) const {
   return GetAuraColor(color_id, this);
 }
 
+bool NativeThemeWin::SupportsNinePatch(Part part) const {
+  return false;
+}
+
+gfx::Size NativeThemeWin::GetNinePatchCanvasSize(Part part) const {
+  NOTREACHED() << "NativeThemeWin doesn't support nine-patch resources.";
+  return gfx::Size();
+}
+
+gfx::Rect NativeThemeWin::GetNinePatchAperture(Part part) const {
+  NOTREACHED() << "NativeThemeWin doesn't support nine-patch resources.";
+  return gfx::Rect();
+}
+
 void NativeThemeWin::PaintIndirect(SkCanvas* destination_canvas,
                                    HDC destination_hdc,
                                    Part part,