Improve positioned/percentHeight descendant/container tracking

third_party/WebKit/Source/core/layout/LayoutBox.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, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. 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 112 matching lines @@
 
     return NoPaintLayer;
 }
 
 void LayoutBox::willBeDestroyed()
 {
     clearOverrideSize();
     clearContainingBlockOverrideSize();
     clearExtraInlineAndBlockOffests();
 
-    LayoutBlock::removePercentHeightDescendantIfNeeded(this);
+    if (isOutOfFlowPositioned())
+        LayoutBlock::removePositionedObject(this);
+    removeFromPercentHeightContainer();
 
     ShapeOutsideInfo::removeInfo(*this);
 
     LayoutBoxModelObject::willBeDestroyed();
 }
 
 void LayoutBox::removeFloatingOrPositionedChildFromBlockLists()
 {
     ASSERT(isFloatingOrOutOfFlowPositioned());
 
@@ skipping 68 matching lines @@
 {
     // Horizontal writing mode definition is updated in LayoutBoxModelObject::updateFromStyle,
     // (as part of the LayoutBoxModelObject::styleDidChange call below). So, we can safely cache the horizontal
     // writing mode value before style change here.
     bool oldHorizontalWritingMode = isHorizontalWritingMode();
 
     LayoutBoxModelObject::styleDidChange(diff, oldStyle);
 
     const ComputedStyle& newStyle = styleRef();
     if (needsLayout() && oldStyle)
-        LayoutBlock::removePercentHeightDescendantIfNeeded(this);
+        removeFromPercentHeightContainer();
 
-    if (LayoutBlock::hasPercentHeightContainerMap() && slowFirstChild()
-        && oldHorizontalWritingMode != isHorizontalWritingMode())
-        LayoutBlock::clearPercentHeightDescendantsFrom(this);
+    if (oldHorizontalWritingMode != isHorizontalWritingMode())
+        clearPercentHeightDescendants();
 
     // If our zoom factor changes and we have a defined scrollLeft/Top, we need to adjust that value into the
     // new zoomed coordinate space.
     if (hasOverflowClip() && oldStyle && oldStyle->effectiveZoom() != newStyle.effectiveZoom() && layer()) {
         if (int left = layer()->scrollableArea()->scrollXOffset()) {
             left = (left / oldStyle->effectiveZoom()) * newStyle.effectiveZoom();
             layer()->scrollableArea()->scrollToXOffset(left);
         }
         if (int top = layer()->scrollableArea()->scrollYOffset()) {
             top = (top / oldStyle->effectiveZoom()) * newStyle.effectiveZoom();
@@ skipping 4671 matching lines @@
     return ShapeOutsideInfo::isEnabledFor(*this) ? ShapeOutsideInfo::info(*this) : nullptr;
 }
 
 void LayoutBox::clearPreviousPaintInvalidationRects()
 {
     LayoutBoxModelObject::clearPreviousPaintInvalidationRects();
     if (PaintLayerScrollableArea* scrollableArea = this->scrollableArea())
         scrollableArea->clearPreviousPaintInvalidationRects();
 }
 
+void LayoutBox::setPercentHeightContainer(LayoutBlock* container)
+{
+    ASSERT(!container || !percentHeightContainer());
+    if (!container && !m_rareData)
+        return;
+    ensureRareData().m_percentHeightContainer = container;
+}
+
+void LayoutBox::removeFromPercentHeightContainer()
+{
+    if (!percentHeightContainer())
+        return;
+
+    ASSERT(percentHeightContainer()->hasPercentHeightDescendant(this));
+    percentHeightContainer()->removePercentHeightDescendant(this);
+    // The above call should call this object's setPercentHeightContainer(nullptr).
+    ASSERT(!percentHeightContainer());
+}
+
+void LayoutBox::clearPercentHeightDescendants()
+{
+    for (LayoutObject* curr = slowFirstChild(); curr; curr = curr->nextInPreOrder(this)) {
+        if (curr->isBox())
+            toLayoutBox(curr)->removeFromPercentHeightContainer();
+    }
+}
+
 } // namespace blink