Revert "Adapt and reland old position sticky implementation from https://codereview.chromium.org/34…

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

Index: third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
diff --git a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
index 4b9bea45cabc186af3dc9e3b7129ba5ea70facfd..ced1bfbed06362ad057b88925c7603bc0716bf4e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBoxModelObject.cpp
@@ -282,34 +282,8 @@ void LayoutBoxModelObject::styleDidChange(StyleDifference diff, const ComputedSt
     }
 
     if (FrameView *frameView = view()->frameView()) {
-        bool newStyleIsViewportConstained = style()->position() == FixedPosition;
-        bool oldStyleIsViewportConstrained = oldStyle && oldStyle->position() == FixedPosition;
-        bool newStyleIsSticky = style()->position() == StickyPosition;
-        bool oldStyleIsSticky = oldStyle && oldStyle->position() == StickyPosition;
-
-        if (newStyleIsSticky != oldStyleIsSticky) {
-            if (newStyleIsSticky) {
-                frameView->addStickyPositionObject();
-                // During compositing inputs update we'll have the scroll
-                // ancestor without having to walk up the tree and can compute
-                // the sticky position constraints then.
-                if (layer())
-                    layer()->setNeedsCompositingInputsUpdate();
-            } else {
-                // This may get re-added to viewport constrained objects if the object went
-                // from sticky to fixed.
-                frameView->removeViewportConstrainedObject(this);
-                frameView->removeStickyPositionObject();
-
-                // Remove sticky constraints for this layer.
-                if (layer()) {
-                    DisableCompositingQueryAsserts disabler;
-                    if (const PaintLayer* ancestorOverflowLayer = layer()->ancestorOverflowLayer())
-                        ancestorOverflowLayer->getScrollableArea()->invalidateStickyConstraintsFor(layer());
-                }
-            }
-        }
-
+        bool newStyleIsViewportConstained = style()->hasViewportConstrainedPosition();
+        bool oldStyleIsViewportConstrained = oldStyle && oldStyle->hasViewportConstrainedPosition();
         if (newStyleIsViewportConstained != oldStyleIsViewportConstrained) {
             if (newStyleIsViewportConstained && layer())
                 frameView->addViewportConstrainedObject(this);
@@ -319,19 +293,6 @@ void LayoutBoxModelObject::styleDidChange(StyleDifference diff, const ComputedSt
     }
 }
 
-void LayoutBoxModelObject::invalidateStickyConstraints()
-{
-    if (!layer())
-        return;
-
-    // This intentionally uses the stale ancestor overflow layer compositing
-    // input as if we have saved constraints for this layer they were saved
-    // in the previous frame.
-    DisableCompositingQueryAsserts disabler;
-    if (const PaintLayer* ancestorOverflowLayer = layer()->ancestorOverflowLayer())
-        ancestorOverflowLayer->getScrollableArea()->invalidateAllStickyConstraints();
-}
-
 void LayoutBoxModelObject::createLayer(PaintLayerType type)
 {
     // If the current paint invalidation container is not a stacking context and this object is
@@ -651,134 +612,6 @@ LayoutSize LayoutBoxModelObject::relativePositionOffset() const
     return offset;
 }
 
-void LayoutBoxModelObject::updateStickyPositionConstraints() const
-{
-    // TODO(flackr): This method is reasonably complicated and should have some direct unit testing.
-    const FloatSize constrainingSize = computeStickyConstrainingRect().size();
-
-    PaintLayerScrollableArea* scrollableArea = layer()->ancestorOverflowLayer()->getScrollableArea();
-    StickyPositionScrollingConstraints constraints;
-    FloatSize skippedContainersOffset;
-    LayoutBlock* containingBlock = this->containingBlock();
-    // Skip anonymous containing blocks.
-    while (containingBlock->isAnonymous()) {
-        skippedContainersOffset += toFloatSize(FloatPoint(containingBlock->frameRect().location()));
-        containingBlock = containingBlock->containingBlock();
-    }
-    LayoutBox* scrollAncestor = layer()->ancestorOverflowLayer()->isRootLayer() ? nullptr : toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
-
-    LayoutRect containerContentRect = containingBlock->contentBoxRect();
-    LayoutUnit maxWidth = containingBlock->availableLogicalWidth();
-
-    // Sticky positioned element ignore any override logical width on the containing block (as they don't call
-    // containingBlockLogicalWidthForContent). It's unclear whether this is totally fine.
-    // Compute the container-relative area within which the sticky element is allowed to move.
-    containerContentRect.contractEdges(
-        minimumValueForLength(style()->marginTop(), maxWidth),
-        minimumValueForLength(style()->marginRight(), maxWidth),
-        minimumValueForLength(style()->marginBottom(), maxWidth),
-        minimumValueForLength(style()->marginLeft(), maxWidth));
-
-    // Map to the scroll ancestor.
-    constraints.setScrollContainerRelativeContainingBlockRect(containingBlock->localToAncestorQuad(FloatRect(containerContentRect), scrollAncestor).boundingBox());
-
-    FloatRect stickyBoxRect = isLayoutInline()
-        ? FloatRect(toLayoutInline(this)->linesBoundingBox())
-        : FloatRect(toLayoutBox(this)->frameRect());
-    FloatRect flippedStickyBoxRect = stickyBoxRect;
-    containingBlock->flipForWritingMode(flippedStickyBoxRect);
-    FloatPoint stickyLocation = flippedStickyBoxRect.location() + skippedContainersOffset;
-
-    // TODO(flackr): Unfortunate to call localToAncestorQuad again, but we can't just offset from the previously computed rect if there are transforms.
-    // Map to the scroll ancestor.
-    FloatRect scrollContainerRelativeContainerFrame = containingBlock->localToAncestorQuad(FloatRect(FloatPoint(), FloatSize(containingBlock->size())), scrollAncestor).boundingBox();
-
-    // If the containing block is our scroll ancestor, its location will not include the scroll offset which we need to include as
-    // part of the sticky box rect so we include it here.
-    if (containingBlock->hasOverflowClip()) {
-        FloatSize scrollOffset(toFloatSize(containingBlock->layer()->getScrollableArea()->adjustedScrollOffset()));
-        stickyLocation -= scrollOffset;
-    }
-
-    constraints.setScrollContainerRelativeStickyBoxRect(FloatRect(scrollContainerRelativeContainerFrame.location() + toFloatSize(stickyLocation), flippedStickyBoxRect.size()));
-
-    // We skip the right or top sticky offset if there is not enough space to honor both the left/right or top/bottom offsets.
-    LayoutUnit horizontalOffsets = minimumValueForLength(style()->right(), LayoutUnit(constrainingSize.width())) +
-        minimumValueForLength(style()->left(), LayoutUnit(constrainingSize.width()));
-    bool skipRight = false;
-    bool skipLeft = false;
-    if (!style()->left().isAuto() && !style()->right().isAuto()) {
-        if (horizontalOffsets > containerContentRect.width()
-            || horizontalOffsets + containerContentRect.width() > constrainingSize.width()) {
-            skipRight = style()->isLeftToRightDirection();
-            skipLeft = !skipRight;
-        }
-    }
-
-    if (!style()->left().isAuto() && !skipLeft) {
-        constraints.setLeftOffset(minimumValueForLength(style()->left(), LayoutUnit(constrainingSize.width())));
-        constraints.addAnchorEdge(StickyPositionScrollingConstraints::AnchorEdgeLeft);
-    }
-
-    if (!style()->right().isAuto() && !skipRight) {
-        constraints.setRightOffset(minimumValueForLength(style()->right(), LayoutUnit(constrainingSize.width())));
-        constraints.addAnchorEdge(StickyPositionScrollingConstraints::AnchorEdgeRight);
-    }
-
-    bool skipBottom = false;
-    // TODO(flackr): Exclude top or bottom edge offset depending on the writing mode when related
-    // sections are fixed in spec: http://lists.w3.org/Archives/Public/www-style/2014May/0286.html
-    LayoutUnit verticalOffsets = minimumValueForLength(style()->top(), LayoutUnit(constrainingSize.height())) +
-        minimumValueForLength(style()->bottom(), LayoutUnit(constrainingSize.height()));
-    if (!style()->top().isAuto() && !style()->bottom().isAuto()) {
-        if (verticalOffsets > containerContentRect.height()
-            || verticalOffsets + containerContentRect.height() > constrainingSize.height()) {
-            skipBottom = true;
-        }
-    }
-
-    if (!style()->top().isAuto()) {
-        constraints.setTopOffset(minimumValueForLength(style()->top(), LayoutUnit(constrainingSize.height())));
-        constraints.addAnchorEdge(StickyPositionScrollingConstraints::AnchorEdgeTop);
-    }
-
-    if (!style()->bottom().isAuto() && !skipBottom) {
-        constraints.setBottomOffset(minimumValueForLength(style()->bottom(), LayoutUnit(constrainingSize.height())));
-        constraints.addAnchorEdge(StickyPositionScrollingConstraints::AnchorEdgeBottom);
-    }
-    scrollableArea->stickyConstraintsMap().set(layer(), constraints);
-}
-
-FloatRect LayoutBoxModelObject::computeStickyConstrainingRect() const
-{
-    if (layer()->ancestorOverflowLayer()->isRootLayer())
-        return view()->frameView()->visibleContentRect();
-
-    LayoutBox* enclosingClippingBox = toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
-    FloatRect constrainingRect;
-    constrainingRect = FloatRect(enclosingClippingBox->overflowClipRect(LayoutPoint()));
-    constrainingRect.move(enclosingClippingBox->paddingLeft(), enclosingClippingBox->paddingTop());
-    constrainingRect.contract(FloatSize(enclosingClippingBox->paddingLeft() + enclosingClippingBox->paddingRight(),
-        enclosingClippingBox->paddingTop() + enclosingClippingBox->paddingBottom()));
-    return constrainingRect;
-}
-
-LayoutSize LayoutBoxModelObject::stickyPositionOffset() const
-{
-    const PaintLayer* ancestorOverflowLayer = layer()->ancestorOverflowLayer();
-    // TODO: Force compositing input update if we ask for offset before compositing inputs have been computed?
-    if (!ancestorOverflowLayer)
-        return LayoutSize();
-    FloatRect constrainingRect = computeStickyConstrainingRect();
-    PaintLayerScrollableArea* scrollableArea = ancestorOverflowLayer->getScrollableArea();
-
-    // The sticky offset is physical, so we can just return the delta computed in absolute coords (though it may be wrong with transforms).
-    // TODO: Force compositing input update if we ask for offset with stale compositing inputs.
-    if (!scrollableArea->stickyConstraintsMap().contains(layer()))
-        return LayoutSize();
-    return LayoutSize(scrollableArea->stickyConstraintsMap().get(layer()).computeStickyOffset(constrainingRect));
-}
-
 LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeToOffsetParent(const LayoutPoint& startPoint) const
 {
     // If the element is the HTML body element or doesn't have a parent
@@ -801,7 +634,7 @@ LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeToOffsetParent(const L
             referencePoint.move(-toLayoutBox(offsetParent)->borderLeft(), -toLayoutBox(offsetParent)->borderTop());
         if (!isOutOfFlowPositioned() || flowThreadContainingBlock()) {
             if (isInFlowPositioned())
-                referencePoint.move(offsetForInFlowPosition());
+                referencePoint.move(relativePositionOffset());
 
             LayoutObject* current;
             for (current = parent(); current != offsetParent && current->parent(); current = current->parent()) {
@@ -823,13 +656,7 @@ LayoutPoint LayoutBoxModelObject::adjustedPositionRelativeToOffsetParent(const L
 
 LayoutSize LayoutBoxModelObject::offsetForInFlowPosition() const
 {
-    if (isRelPositioned())
-        return relativePositionOffset();
-
-    if (isStickyPositioned())
-        return stickyPositionOffset();
-
-    return LayoutSize();
+    return isRelPositioned() ? relativePositionOffset() : LayoutSize();
 }
 
 LayoutUnit LayoutBoxModelObject::offsetLeft() const
@@ -1068,10 +895,10 @@ const LayoutObject* LayoutBoxModelObject::pushMappingToContainer(const LayoutBox
         TransformationMatrix t;
         getTransformFromContainer(container, containerOffset, t);
         t.translateRight(adjustmentForSkippedAncestor.width().toFloat(), adjustmentForSkippedAncestor.height().toFloat());
-        geometryMap.push(this, t, flags, LayoutSize());
+        geometryMap.push(this, t, flags);
     } else {
         containerOffset += adjustmentForSkippedAncestor;
-        geometryMap.push(this, containerOffset, flags, LayoutSize());
+        geometryMap.push(this, containerOffset, flags);
     }
 
     return ancestorSkipped ? ancestorToStopAt : container;