Support mask images for filter-based -webkit-box-reflect.

third_party/WebKit/Source/core/paint/BoxReflectionUtils.h

+// Copyright 2016 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.
+
+#ifndef BoxReflectionUtils_h
+#define BoxReflectionUtils_h
+
+namespace blink {
+
+class BoxReflection;
+class ComputedStyle;
+class PaintLayer;
+
+// Utilities for manipulating box reflections in terms of core concepts, like
+// PaintLayer.
+BoxReflection boxReflectionForPaintLayer(const PaintLayer&, const ComputedStyle&);
+
+} // namespace blink
+
+#endif // BoxReflectionUtils_h