Add offset contributed to sticky position box rect by location containers

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 761 matching lines @@
 }
 
 void LayoutBoxModelObject::updateStickyPositionConstraints() const {
   const FloatSize constrainingSize = computeStickyConstrainingRect().size();
 
   PaintLayerScrollableArea* scrollableArea =
       layer()->ancestorOverflowLayer()->getScrollableArea();
   StickyPositionScrollingConstraints constraints;
   FloatSize skippedContainersOffset;
   LayoutBlock* containingBlock = this->containingBlock();
+  // The location container for boxes is not always the containing block.
+  LayoutBox* locationContainer = isLayoutInline()
+                                     ? containingBlock
+                                     : toLayoutBox(this)->locationContainer();
   // Skip anonymous containing blocks.
   while (containingBlock->isAnonymous()) {
-    skippedContainersOffset +=
-        toFloatSize(FloatPoint(containingBlock->frameRect().location()));
     containingBlock = containingBlock->containingBlock();
   }
+  MapCoordinatesFlags flags = 0;
+  skippedContainersOffset =
+      toFloatSize(locationContainer
+                      ->localToAncestorQuadWithoutTransforms(
+                          FloatQuad(), containingBlock, flags)
+                      .boundingBox()
+                      .location());
   LayoutBox* scrollAncestor =
       layer()->ancestorOverflowLayer()->isRootLayer()
           ? nullptr
           : toLayoutBox(layer()->ancestorOverflowLayer()->layoutObject());
 
   LayoutUnit maxContainerWidth =
       containingBlock->isLayoutView()
           ? containingBlock->logicalWidth()
           : containingBlock->containingBlockLogicalWidthForContent();
   // 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.
   LayoutUnit maxWidth = containingBlock->availableLogicalWidth();
 
   // Map the containing block to the inner corner of the scroll ancestor without
   // transforms.
   FloatRect scrollContainerRelativePaddingBoxRect(
       containingBlock->layoutOverflowRect());
   FloatSize scrollContainerBorderOffset;
   if (scrollAncestor) {
     scrollContainerBorderOffset =
         FloatSize(scrollAncestor->borderLeft(), scrollAncestor->borderTop());
   }
   if (containingBlock != scrollAncestor) {
     FloatQuad localQuad(FloatRect(containingBlock->paddingBoxRect()));
-    TransformState transformState(TransformState::ApplyTransformDirection,
-                                  localQuad.boundingBox().center(), localQuad);
-    containingBlock->mapLocalToAncestor(scrollAncestor, transformState,
-                                        ApplyContainerFlip);
-    transformState.flatten();
     scrollContainerRelativePaddingBoxRect =
-        transformState.lastPlanarQuad().boundingBox();
+        containingBlock
+            ->localToAncestorQuadWithoutTransforms(localQuad, scrollAncestor,
+                                                   flags)
+            .boundingBox();
 
     // The sticky position constraint rects should be independent of the current
     // scroll position, so after mapping we add in the scroll position to get
     // the container's position within the ancestor scroller's unscrolled layout
     // overflow.
     ScrollOffset scrollOffset(
         scrollAncestor
             ? toFloatSize(scrollAncestor->getScrollableArea()->scrollPosition())
             : FloatSize());
     scrollContainerRelativePaddingBoxRect.move(scrollOffset);
@@ skipping 513 matching lines @@
   if (rootElementStyle->hasBackground())
     return false;
 
   if (node() != document().firstBodyElement())
     return false;
 
   return true;
 }
 
 }  // namespace blink