Revert of Compute snap offsets (both repeat and element based)

third_party/WebKit/Source/core/layout/LayoutBox.h

Index: third_party/WebKit/Source/core/layout/LayoutBox.h
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.h b/third_party/WebKit/Source/core/layout/LayoutBox.h
index da436032df5683107a4c55c8796525171929d811..7c7e4cc71b880abda77f470318c411f4334ddb4d 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.h
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.h
@@ -57,8 +57,6 @@ enum ApplyOverflowClipFlag {
     ApplyNonScrollOverflowClip
 };
 
-using SnapAreaSet = HashSet<const LayoutBox*>;
-
 struct LayoutBoxRareData {
     WTF_MAKE_NONCOPYABLE(LayoutBoxRareData); USING_FAST_MALLOC(LayoutBoxRareData);
 public:
@@ -68,8 +66,6 @@ public:
         , m_overrideLogicalContentWidth(-1)
         , m_previousBorderBoxSize(LayoutUnit(-1), LayoutUnit(-1))
         , m_percentHeightContainer(nullptr)
-        , m_snapContainer(nullptr)
-        , m_snapAreas(nullptr)
     {
     }
 
@@ -89,19 +85,6 @@ public:
     LayoutUnit m_paginationStrut;
 
     LayoutBlock* m_percentHeightContainer;
-    // For snap area, the owning snap container.
-    LayoutBox* m_snapContainer;
-    // For snap container, the descendant snap areas that contribute snap
-    // points.
-    OwnPtr<SnapAreaSet> m_snapAreas;
-
-    SnapAreaSet& ensureSnapAreas()
-    {
-        if (!m_snapAreas)
-            m_snapAreas = adoptPtr(new SnapAreaSet);
-
-        return *m_snapAreas;
-    }
 };
 
 // LayoutBox implements the full CSS box model.
@@ -934,12 +917,6 @@ public:
     void setPercentHeightContainer(LayoutBlock*);
     void removeFromPercentHeightContainer();
     void clearPercentHeightDescendants();
-    // For snap areas, returns the snap container that owns us.
-    LayoutBox* snapContainer() const;
-    void setSnapContainer(LayoutBox*);
-    // For snap containers, returns all associated snap areas.
-    SnapAreaSet* snapAreas() const;
-    void clearSnapAreas();
 
     bool hitTestClippedOutByRoundedBorder(const HitTestLocation& locationInContainer, const LayoutPoint& borderBoxLocation) const;
 
@@ -1001,9 +978,6 @@ private:
 
     void updateShapeOutsideInfoAfterStyleChange(const ComputedStyle&, const ComputedStyle* oldStyle);
     void updateGridPositionAfterStyleChange(const ComputedStyle*);
-    void updateScrollSnapMappingAfterStyleChange(const ComputedStyle*, const ComputedStyle* oldStyle);
-    void clearScrollSnapMapping();
-    void addScrollSnapMapping();
 
     bool autoWidthShouldFitContent() const;
     LayoutUnit shrinkToFitLogicalWidth(LayoutUnit availableLogicalWidth, LayoutUnit bordersPlusPadding) const;
@@ -1089,9 +1063,6 @@ private:
 
     LayoutRectOutsets m_marginBoxOutsets;
 
-    void addSnapArea(const LayoutBox&);
-    void removeSnapArea(const LayoutBox&);
-
 protected:
     // The logical width of the element if it were to break its lines at every
     // possible opportunity.