Implement the framework for a paint property hierarchy

third_party/WebKit/Source/platform/graphics/paint/TransformPaintPropertyNode.h

+// Copyright 2015 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 TransformPaintPropertyNode_h
+#define TransformPaintPropertyNode_h
+
+#include "platform/PlatformExport.h"
+#include "platform/geometry/FloatPoint3D.h"
+#include "platform/transforms/TransformationMatrix.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefCounted.h"
+#include "wtf/RefPtr.h"
+
+#include <iosfwd>
+
+namespace blink {
+
+// A transform created by a css property such as "transform" or "perspective"
+// along with a reference to the parent TransformPaintPropertyNode, or nullptr
+// for the root.
+class PLATFORM_EXPORT TransformPaintPropertyNode : public RefCounted<TransformPaintPropertyNode> {
+public:
+    TransformPaintPropertyNode(const TransformationMatrix& matrix, const FloatPoint3D& origin, PassRefPtr<TransformPaintPropertyNode> parent = nullptr)
+        : m_matrix(matrix), m_origin(origin), m_parent(parent) { }
+
+    const TransformationMatrix& matrix() const { return m_matrix; }
+    const FloatPoint3D& origin() const { return m_origin; }
+
+    // Parent transform that this transform is relative to, or nullptr if this
+    // is the root transform.
+    const TransformPaintPropertyNode* parent() const { return m_parent.get(); }
+
+private:
+    const TransformationMatrix m_matrix;
+    const FloatPoint3D m_origin;
+    RefPtr<TransformPaintPropertyNode> m_parent;
+};
+
+// Redeclared here to avoid ODR issues.
+// See platform/testing/PaintPrinters.h.
+void PrintTo(const TransformPaintPropertyNode&, std::ostream*);
+
+} // namespace blink
+
+#endif // TransformPaintPropertyNode_h