Implement the framework for a paint property hierarchy

third_party/WebKit/Source/core/paint/ObjectPaintProperties.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 ObjectPaintProperties_h
+#define ObjectPaintProperties_h
+
+#include "platform/graphics/paint/TransformPaintPropertyNode.h"
+#include "wtf/PassRefPtr.h"
+#include "wtf/RefPtr.h"
+
+namespace blink {
+
+// The minimal set of paint properties created by a |LayoutObject|. These
+// properties encode a hierachy of transforms, clips, effects, etc, both between
+// LayoutObjects (each property has a parent) and among the properties of a
+// single LayoutObject (e.g., transform and perspective with the correct parent
+// relationship to represent ordering).
+class ObjectPaintProperties {

[chrishtr, 2015/10/07 20:55:56]

How about getting rid of this class and using graphics/paint/PaintProperties.h?
With the semantic that a null refptr means that paint property is not set on
this object and hence is inherited.

+    WTF_MAKE_NONCOPYABLE(ObjectPaintProperties);
+    WTF_MAKE_FAST_ALLOCATED(ObjectPaintProperties);
+public:
+    static PassOwnPtr<ObjectPaintProperties> create()
+    {
+        return adoptPtr(new ObjectPaintProperties());
+    }
+
+    bool hasTransform() const { return m_transform; }
+    void setTransform(PassRefPtr<TransformPaintPropertyNode> transform) { m_transform = transform; }
+    TransformPaintPropertyNode* transform() { return m_transform.get(); }
+
+    bool hasPerspective() const { return m_perspective; }
+    void setPerspective(PassRefPtr<TransformPaintPropertyNode> perspective) { m_perspective = perspective; }
+    TransformPaintPropertyNode* perspective() { return m_perspective.get(); }
+
+private:
+    ObjectPaintProperties() { }
+
+    RefPtr<TransformPaintPropertyNode> m_transform;
+    RefPtr<TransformPaintPropertyNode> m_perspective;
+};
+
+} // namespace blink
+
+#endif // ObjectPaintProperties_h