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

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

Index: third_party/WebKit/Source/core/layout/LayoutBox.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBox.cpp b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
index 3d59dbba898111d07260a41c2ad8b80666a781fc..1c72db18a5e3d889ed463b69574fc7d61d53be61 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -56,7 +56,6 @@
 #include "core/layout/shapes/ShapeOutsideInfo.h"
 #include "core/page/AutoscrollController.h"
 #include "core/page/Page.h"
-#include "core/page/scrolling/SnapCoordinator.h"
 #include "core/paint/BackgroundImageGeometry.h"
 #include "core/paint/BoxPainter.h"
 #include "core/paint/PaintLayer.h"
@@ -146,7 +145,6 @@ void LayoutBox::willBeDestroyed()
 void LayoutBox::insertedIntoTree()
 {
     LayoutBoxModelObject::insertedIntoTree();
-    addScrollSnapMapping();
 
     if (isOrthogonalWritingModeRoot())
         markOrthogonalWritingModeRoot();
@@ -157,7 +155,6 @@ void LayoutBox::willBeRemovedFromTree()
     if (!documentBeingDestroyed() && isOrthogonalWritingModeRoot())
         unmarkOrthogonalWritingModeRoot();
 
-    clearScrollSnapMapping();
     LayoutBoxModelObject::willBeRemovedFromTree();
 }
 
@@ -304,8 +301,6 @@ void LayoutBox::styleDidChange(StyleDifference diff, const ComputedStyle* oldSty
         LayoutFlowThread* flowThread = flowThreadContainingBlock();
         if (flowThread && flowThread != this)
             flowThread->flowThreadDescendantStyleDidChange(this, diff, *oldStyle);
-
-        updateScrollSnapMappingAfterStyleChange(&newStyle, oldStyle);
     }
 
     ASSERT(!isInline() || isAtomicInlineLevel()); // Non-atomic inlines should be LayoutInline or LayoutText, not LayoutBox.
@@ -378,38 +373,6 @@ void LayoutBox::updateGridPositionAfterStyleChange(const ComputedStyle* oldStyle
     toLayoutGrid(parent())->dirtyGrid();
 }
 
-void LayoutBox::updateScrollSnapMappingAfterStyleChange(const ComputedStyle* newStyle, const ComputedStyle* oldStyle)
-{
-    SnapCoordinator* snapCoordinator = document().snapCoordinator();
-    if (!snapCoordinator)
-        return;
-
-    // Scroll snap type has no effect on the viewport defining element instead
-    // they are handled by the LayoutView.
-    bool allowsSnapContainer = node() != document().viewportDefiningElement();
-
-    ScrollSnapType oldSnapType = oldStyle ? oldStyle->getScrollSnapType() : ScrollSnapTypeNone;
-    ScrollSnapType newSnapType = newStyle && allowsSnapContainer ? newStyle->getScrollSnapType() : ScrollSnapTypeNone;
-    if (oldSnapType != newSnapType)
-        snapCoordinator->snapContainerDidChange(*this, newSnapType);
-
-    Vector<LengthPoint> emptyVector;
-    const Vector<LengthPoint>& oldSnapCoordinate = oldStyle ? oldStyle->scrollSnapCoordinate() : emptyVector;
-    const Vector<LengthPoint>& newSnapCoordinate = newStyle ? newStyle->scrollSnapCoordinate() : emptyVector;
-    if (oldSnapCoordinate != newSnapCoordinate)
-        snapCoordinator->snapAreaDidChange(*this, newSnapCoordinate);
-}
-
-void LayoutBox::addScrollSnapMapping()
-{
-    updateScrollSnapMappingAfterStyleChange(style(), nullptr);
-}
-
-void LayoutBox::clearScrollSnapMapping()
-{
-    updateScrollSnapMappingAfterStyleChange(nullptr, style());
-}
-
 void LayoutBox::updateFromStyle()
 {
     LayoutBoxModelObject::updateFromStyle();
@@ -4815,50 +4778,4 @@ void LayoutBox::clearPercentHeightDescendants()
     }
 }
 
-LayoutBox* LayoutBox::snapContainer() const
-{
-    return m_rareData ? m_rareData->m_snapContainer : nullptr;
-}
-
-void LayoutBox::setSnapContainer(LayoutBox* newContainer)
-{
-    LayoutBox* oldContainer = snapContainer();
-    if (oldContainer == newContainer)
-        return;
-
-    if (oldContainer)
-        oldContainer->removeSnapArea(*this);
-
-    ensureRareData().m_snapContainer = newContainer;
-
-    if (newContainer)
-        newContainer->addSnapArea(*this);
-}
-
-void LayoutBox::clearSnapAreas()
-{
-    if (SnapAreaSet* areas = snapAreas()) {
-        for (auto& snapArea : *areas)
-            snapArea->m_rareData->m_snapContainer = nullptr;
-        areas->clear();
-    }
-}
-
-void LayoutBox::addSnapArea(const LayoutBox& snapArea)
-{
-    ensureRareData().ensureSnapAreas().add(&snapArea);
-}
-
-void LayoutBox::removeSnapArea(const LayoutBox& snapArea)
-{
-    if (m_rareData && m_rareData->m_snapAreas) {
-        m_rareData->m_snapAreas->remove(&snapArea);
-    }
-}
-
-SnapAreaSet* LayoutBox::snapAreas() const
-{
-    return m_rareData ? m_rareData->m_snapAreas.get() : nullptr;
-}
-
 } // namespace blink