Define contentsProperties on ObjectPaintProperties, for use in paint invalidation.

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 "core/CoreExport.h"
 #include "platform/geometry/LayoutPoint.h"
 #include "platform/graphics/paint/ClipPaintPropertyNode.h"
@@ skipping 41 matching lines @@
     const TransformPaintPropertyNode* transform() const { return m_transform.get(); }
     const TransformPaintPropertyNode* perspective() const { return m_perspective.get(); }
     const TransformPaintPropertyNode* svgLocalToBorderBoxTransform() const { return m_svgLocalToBorderBoxTransform.get(); }
     const TransformPaintPropertyNode* scrollTranslation() const { return m_scrollTranslation.get(); }
     const TransformPaintPropertyNode* scrollbarPaintOffset() const { return m_scrollbarPaintOffset.get(); }
 
     const EffectPaintPropertyNode* effect() const { return m_effect.get(); }
 
     // The hierarchy of the clip subtree created by a LayoutObject is as follows:
     // [ css clip ]
+    // [ css clip fixed position]
     // |
     // +--- [ overflow clip ]
     const ClipPaintPropertyNode* cssClip() const { return m_cssClip.get(); }
     const ClipPaintPropertyNode* cssClipFixedPosition() const { return m_cssClipFixedPosition.get(); }
     const ClipPaintPropertyNode* overflowClip() const { return m_overflowClip.get(); }
 
     // This is a complete set of property nodes that should be used as a starting point to paint
     // this layout object. It is needed becauase some property inherits from the containing block,
     // not painting parent, thus can't be derived in O(1) during paint walk.
     // Note: If this layout object has transform or stacking-context effects, those are already
     // baked into in the context here. However for properties that affects only children,
     // for example, perspective and overflow clip, those should be applied by the painter
     // at the right painting step.
     struct LocalBorderBoxProperties {
         LayoutPoint paintOffset;
         PropertyTreeState propertyTreeState;
     };
     const LocalBorderBoxProperties* localBorderBoxProperties() const { return m_localBorderBoxProperties.get(); }
+    // ContentsProperties is the PropertyTreeState state that is the same as in localBorderBoxProperties, except that it is inside
+    // any clips and scrolls caused by this object. This PropertyTreeState is suitable as the destination for paint invalidation.
+    void getContentsProperties(PropertyTreeState&) const;
 
     void clearPaintOffsetTranslation() { m_paintOffsetTranslation = nullptr; }
     void clearTransform() { m_transform = nullptr; }
     void clearEffect() { m_effect = nullptr; }
     void clearCssClip() { m_cssClip = nullptr; }
     void clearCssClipFixedPosition() { m_cssClipFixedPosition = nullptr; }
     void clearOverflowClip() { m_overflowClip = nullptr; }
     void clearPerspective() { m_perspective = nullptr; }
     void clearSvgLocalToBorderBoxTransform() { m_svgLocalToBorderBoxTransform = nullptr; }
     void clearScrollTranslation() { m_scrollTranslation = nullptr; }
@@ skipping 44 matching lines @@
     RefPtr<TransformPaintPropertyNode> m_svgLocalToBorderBoxTransform;
     RefPtr<TransformPaintPropertyNode> m_scrollTranslation;
     RefPtr<TransformPaintPropertyNode> m_scrollbarPaintOffset;
 
     std::unique_ptr<LocalBorderBoxProperties> m_localBorderBoxProperties;
 };
 
 } // namespace blink
 
 #endif // ObjectPaintProperties_h