Refactor RenderThemeChromiumDefault

Source/core/rendering/RenderThemeChromiumWin.cpp

+// 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 "config.h"
+#include "core/rendering/RenderThemeChromiumWin.h"
+
+namespace blink {
+
+PassRefPtr<RenderTheme> RenderThemeChromiumWin::create()
+{
+    return adoptRef(new RenderThemeChromiumWin());
+}
+
+RenderTheme& RenderTheme::theme()
+{
+    DEFINE_STATIC_REF(RenderTheme, renderTheme, (RenderThemeChromiumWin::create()));
+    return *renderTheme;
+}
+
+} // namespace blink