[CSS Regions] Add new regionOversetChange event

Source/core/rendering/RenderRegion.cpp

Index: Source/core/rendering/RenderRegion.cpp
diff --git a/Source/core/rendering/RenderRegion.cpp b/Source/core/rendering/RenderRegion.cpp
index 5bb9041da655144e110583a36d6ee676f244f705..4260157beea2e85a614fa95c58c4e8d60f42cfb3 100644
--- a/Source/core/rendering/RenderRegion.cpp
+++ b/Source/core/rendering/RenderRegion.cpp
@@ -48,7 +48,6 @@ RenderRegion::RenderRegion(Element* element, RenderFlowThread* flowThread)
     , m_isValid(false)
     , m_hasCustomRegionStyle(false)
     , m_hasAutoLogicalHeight(false)
-    , m_regionState(RegionUndefined)
 {
 }
 
@@ -126,6 +125,20 @@ LayoutRect RenderRegion::overflowRectForFlowThreadPortion(const LayoutRect& flow
     return clipRect;
 }
 
+RegionOversetState RenderRegion::regionOversetState() const
+{
+    if (isValid() && node() && node()->isElementNode())
+        return toElement(node())->regionOversetState();
+
+    return RegionUndefined;
+}
+
+void RenderRegion::setRegionOversetState(RegionOversetState state)
+{
+    if (node() && node()->isElementNode())
+        toElement(node())->setRegionOversetState(state);
+}
+
 LayoutUnit RenderRegion::pageLogicalTopForOffset(LayoutUnit /* offset */) const
 {
     return flowThread()->isHorizontalWritingMode() ? flowThreadPortionRect().y() : flowThreadPortionRect().x();