*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/RootInlineBox.h

Index: Source/core/rendering/RootInlineBox.h
diff --git a/Source/core/rendering/RootInlineBox.h b/Source/core/rendering/RootInlineBox.h
index f944767f19c8d57ae290edb3d2e4ce5a66235f9d..e8911f22fa6b01320a3d0e3ae8728c6c9dd5f7f3 100644
--- a/Source/core/rendering/RootInlineBox.h
+++ b/Source/core/rendering/RootInlineBox.h
@@ -29,7 +29,6 @@ namespace WebCore {
 class EllipsisBox;
 class HitTestResult;
 class RenderBlockFlow;
-class RenderRegion;
 
 struct BidiStatus;
 struct GapRects;
@@ -64,9 +63,6 @@ public:
     LayoutUnit paginatedLineWidth() const { return m_fragmentationData ? m_fragmentationData->m_paginatedLineWidth : LayoutUnit(0); }
     void setPaginatedLineWidth(LayoutUnit width) { ensureLineFragmentationData()->m_paginatedLineWidth = width; }
 
-    RenderRegion* containingRegion() const;
-    void setContainingRegion(RenderRegion*);
-
     LayoutUnit selectionTop() const;
     LayoutUnit selectionBottom() const;
     LayoutUnit selectionHeight() const { return max<LayoutUnit>(0, selectionBottom() - selectionTop()); }
@@ -223,8 +219,7 @@ private:
         WTF_MAKE_NONCOPYABLE(LineFragmentationData); WTF_MAKE_FAST_ALLOCATED;
     public:
         LineFragmentationData()
-            : m_containingRegion(0)
-            , m_paginationStrut(0)
+            : m_paginationStrut(0)
             , m_paginatedLineWidth(0)
             , m_isFirstAfterPageBreak(false)
         {
@@ -233,7 +228,6 @@ private:
 
         // It should not be assumed the |containingRegion| is always valid.
         // It can also be 0 if the flow has no region chain.
-        RenderRegion* m_containingRegion;
         LayoutUnit m_paginationStrut;
         LayoutUnit m_paginatedLineWidth;
         bool m_isFirstAfterPageBreak;