Fixes crash in unittests. This happened as the result of making the

ui/base/native_theme/native_theme_aura.cc

 // 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.
 
 #include "ui/base/native_theme/native_theme_aura.h"
 
 #include "base/logging.h"
 #include "grit/ui_resources.h"
 #include "ui/base/layout.h"
 #include "ui/base/resource/resource_bundle.h"
@@ skipping 35 matching lines @@
     SkColorSetARGB(0x54, 0x60, 0xA8, 0xEB);
 const SkColor kTextfieldSelectionBackgroundUnfocused = SK_ColorLTGRAY;
 const SkColor kTextfieldSelectionColor =
     color_utils::AlphaBlend(SK_ColorBLACK,
         kTextfieldSelectionBackgroundFocused, 0xdd);
 
 }  // namespace
 
 namespace ui {
 
-#if !defined(OS_WIN)
 // static
 NativeTheme* NativeTheme::instance() {
   return NativeThemeAura::instance();
 }
-#endif
 
 // static
 NativeThemeAura* NativeThemeAura::instance() {
   CR_DEFINE_STATIC_LOCAL(NativeThemeAura, s_native_theme, ());
   return &s_native_theme;
 }
 
 NativeThemeAura::NativeThemeAura() {
   // We don't draw scrollbar buttons.
   set_scrollbar_button_length(0);
@@ skipping 217 matching lines @@
       DrawTiledImage(canvas, *center,
                      0, 0, 1.0, 1.0,
                      rect.x() + left->width(), rect.y(),
                      rect.width() - left->width() - right->width(),
                      center->height());
     }
   }
 }
 
 }  // namespace ui