Preliminary paint property walk implementation for SPv2

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/HashMap.h"
+#include "wtf/OwnPtr.h"
+#include "wtf/PassOwnPtr.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).
 //
 // This differs from |PaintChunkProperties| because it can store multiple
 // properties of the same type (e.g., transform and perspective which are both
 // transforms).
 class ObjectPaintProperties {
     WTF_MAKE_NONCOPYABLE(ObjectPaintProperties);
     WTF_MAKE_FAST_ALLOCATED(ObjectPaintProperties);
 public:
     static PassOwnPtr<ObjectPaintProperties> create()
     {
         return adoptPtr(new ObjectPaintProperties());
     }
 
-    bool hasTransform() const { return m_transform; }
+    // The hierarchy of transform subtree created by a LayoutObject.
+    // [ preTranslation ]                   Normally paint offset is accumulated without creating a node
+    // |                                    until we see, for example, transform or position:fixed.
+    // +---[ transform ]                    The space created by CSS transform.
+    //     +---[ perspective ]              The space created by CSS perspective.
+    //         +---[ scrollTranslation ]    The space created by overflow clip.
+    void setPreTranslation(PassRefPtr<TransformPaintPropertyNode> preTranslation) { m_preTranslation = preTranslation; }
+    const TransformPaintPropertyNode* preTranslation() const { return m_preTranslation.get(); }
+
     void setTransform(PassRefPtr<TransformPaintPropertyNode> transform) { m_transform = transform; }
     const TransformPaintPropertyNode* transform() const { return m_transform.get(); }
 
-    bool hasPerspective() const { return m_perspective; }
     void setPerspective(PassRefPtr<TransformPaintPropertyNode> perspective) { m_perspective = perspective; }
     const TransformPaintPropertyNode* perspective() const { return m_perspective.get(); }
 
+    void setScrollTranslation(PassRefPtr<TransformPaintPropertyNode> scrollTranslation) { m_scrollTranslation = scrollTranslation; }
+    const TransformPaintPropertyNode* scrollTranslation() const { return m_scrollTranslation.get(); }
+
 private:
     ObjectPaintProperties() { }
 
+    RefPtr<TransformPaintPropertyNode> m_preTranslation;
     RefPtr<TransformPaintPropertyNode> m_transform;
     RefPtr<TransformPaintPropertyNode> m_perspective;
+    RefPtr<TransformPaintPropertyNode> m_scrollTranslation;

[pdr., 2015/10/15 23:50:50]

I really recommend we leave all overflow:scroll, sticky, and fixedpos issues for
followups. Without scroll nodes these will be hard to really test, and they add
unnecessary complexity at this stage.

 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h