Implement -webkit-box-reflect as a filter.

third_party/WebKit/Source/platform/graphics/filters/FEBoxReflect.cpp

Index: third_party/WebKit/Source/platform/graphics/filters/FEBoxReflect.cpp
diff --git a/third_party/WebKit/Source/platform/graphics/filters/FEBoxReflect.cpp b/third_party/WebKit/Source/platform/graphics/filters/FEBoxReflect.cpp
new file mode 100644
index 0000000000000000000000000000000000000000..a7c41db1cf732ecd9d478e076ec50c07b1ad7b22
--- /dev/null
+++ b/third_party/WebKit/Source/platform/graphics/filters/FEBoxReflect.cpp
@@ -0,0 +1,59 @@
+// 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.
+
+#include "platform/graphics/filters/FEBoxReflect.h"
+
+#include "platform/geometry/FloatRect.h"
+#include "platform/graphics/filters/SkiaImageFilterBuilder.h"
+#include "wtf/Assertions.h"
+
+namespace blink {
+
+PassRefPtrWillBeRawPtr<FEBoxReflect> FEBoxReflect::create(Filter* filter, ReflectionDirection direction, float offset)
+{
+    return adoptRefWillBeNoop(new FEBoxReflect(filter, direction, offset));
+}
+
+FEBoxReflect::FEBoxReflect(Filter* filter, ReflectionDirection direction, float offset)
+    : FilterEffect(filter)
+    , m_reflectionDirection(direction)
+    , m_offset(offset)
+{
+}
+
+FEBoxReflect::~FEBoxReflect()
+{
+}
+
+FloatRect FEBoxReflect::mapRect(const FloatRect& rect, bool forward)
+{
+    SkMatrix flipMatrix = SkiaImageFilterBuilder().matrixForBoxReflectFilter(
+        m_reflectionDirection, m_offset);
+    if (!forward) {
+        bool inverted = flipMatrix.invert(&flipMatrix);
+        DCHECK(inverted) << "box reflect matrix must be invertible";
+    }
+
+    SkRect reflection(rect);
+    flipMatrix.mapRect(&reflection);
+
+    FloatRect result = rect;
+    result.unite(reflection);
+    return result;
+}
+
+TextStream& FEBoxReflect::externalRepresentation(TextStream& ts, int indent) const
+{
+    // Only called for SVG layout tree printing.
+    ASSERT_NOT_REACHED();
+    return ts;
+}
+
+PassRefPtr<SkImageFilter> FEBoxReflect::createImageFilter(SkiaImageFilterBuilder& builder)
+{
+    RefPtr<SkImageFilter> input(builder.build(inputEffect(0), operatingColorSpace()));
+    return builder.buildBoxReflectFilter(m_reflectionDirection, m_offset, nullptr, input.get());
+}
+
+} // namespace blink