List marker pseudo elements.

Source/core/layout/LayoutListItem.h

Index: Source/core/layout/LayoutListItem.h
diff --git a/Source/core/layout/LayoutListItem.h b/Source/core/layout/LayoutListItem.h
index 919f30a6e9d2c65ca1af394cb1425f5eaf5b296e..65658de749344bce73e6c4be509d5c70da6b8804 100644
--- a/Source/core/layout/LayoutListItem.h
+++ b/Source/core/layout/LayoutListItem.h
@@ -60,6 +60,9 @@ public:
 
     bool isEmpty() const;
 
+    void setMarker(LayoutListMarker* marker) { m_marker = marker; }
+    LayoutListMarker* marker() const { return m_marker; }
+
     virtual const char* name() const override { return "LayoutListItem"; }
 
 private:
@@ -70,6 +73,8 @@ private:
     virtual void insertedIntoTree() override;
     virtual void willBeRemovedFromTree() override;
 
+    virtual void subtreeDidChange() override;
+
     virtual void paint(const PaintInfo&, const LayoutPoint&) override;
 
     virtual void layout() override;
@@ -78,7 +83,7 @@ private:
     bool updateMarkerLocation();
     void updateMarkerLocationAndInvalidateWidth();
 
-    void positionListMarker();
+    void positionListMarker(LayoutListMarker*);
 
     virtual void styleDidChange(StyleDifference, const ComputedStyle* oldStyle) override;
 
@@ -89,7 +94,7 @@ private:
     void explicitValueChanged();
 
     int m_explicitValue;
-    LayoutListMarker* m_marker;
+    LayoutListMarker* m_marker; // Not owned when using listMarkerPseudoElements.
     mutable int m_value;
 
     bool m_hasExplicitValue : 1;