Partial revert of https://codereview.chromium.org/1911973002/

ui/native_theme/native_theme_aurawin.cc

-// 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.
-
-#include "ui/native_theme/native_theme_aurawin.h"
-
-#include "third_party/skia/include/core/SkCanvas.h"
-#include "ui/native_theme/common_theme.h"
-#include "ui/native_theme/native_theme_win.h"
-
-namespace ui {
-
-namespace {
-
-bool IsScrollbarPart(NativeTheme::Part part) {
-  switch (part) {
-    case NativeTheme::kScrollbarDownArrow:
-    case NativeTheme::kScrollbarLeftArrow:
-    case NativeTheme::kScrollbarRightArrow:
-    case NativeTheme::kScrollbarUpArrow:
-    case NativeTheme::kScrollbarHorizontalThumb:
-    case NativeTheme::kScrollbarVerticalThumb:
-    case NativeTheme::kScrollbarHorizontalTrack:
-    case NativeTheme::kScrollbarVerticalTrack:
-    case NativeTheme::kScrollbarHorizontalGripper:
-    case NativeTheme::kScrollbarVerticalGripper:
-    case NativeTheme::kScrollbarCorner:
-      return true;
-    default:
-      return false;
-  }
-}
-
-}  // namespace
-
-// static
-NativeTheme* NativeTheme::GetInstanceForWeb() {
-  return NativeThemeAuraWin::instance();
-}
-
-// static
-NativeThemeAura* NativeThemeAura::instance() {
-  return NativeThemeAuraWin::instance();
-}
-
-// static
-NativeThemeAuraWin* NativeThemeAuraWin::instance() {
-  CR_DEFINE_STATIC_LOCAL(NativeThemeAuraWin, s_native_theme, ());
-  return &s_native_theme;
-}
-
-NativeThemeAuraWin::NativeThemeAuraWin() {
-}
-
-NativeThemeAuraWin::~NativeThemeAuraWin() {
-}
-
-void NativeThemeAuraWin::Paint(SkCanvas* canvas,
-                               Part part,
-                               State state,
-                               const gfx::Rect& rect,
-                               const ExtraParams& extra) const {
-  if (IsScrollbarPart(part) &&
-      NativeThemeWin::instance()->IsUsingHighContrastTheme()) {
-    NativeThemeWin::instance()->Paint(canvas, part, state, rect, extra);
-    return;
-  }
-
-  NativeThemeAura::Paint(canvas, part, state, rect, extra);
-}
-
-gfx::Size NativeThemeAuraWin::GetPartSize(Part part,
-                                          State state,
-                                          const ExtraParams& extra) const {
-  // We want aura on windows to use the same size for scrollbars as we would in
-  // the native theme.
-  if (IsScrollbarPart(part))
-    return NativeThemeWin::instance()->GetPartSize(part, state, extra);
-
-  return NativeThemeAura::GetPartSize(part, state, extra);
-}
-
-}  // namespace ui