Improve positioned/percentHeight descendant/container tracking

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 e7dde710055129368066dc36d0f2f12cd54851cf..41f6f14d1b808b5e9edb750a2622daff0b99831e 100644
--- a/third_party/WebKit/Source/core/layout/LayoutBox.cpp
+++ b/third_party/WebKit/Source/core/layout/LayoutBox.cpp
@@ -119,7 +119,8 @@ void LayoutBox::willBeDestroyed()
     clearContainingBlockOverrideSize();
     clearExtraInlineAndBlockOffests();
 
-    LayoutBlock::removePercentHeightDescendantIfNeeded(this);
+    removeFromPositionedContainer();
+    removeFromPercentHeightContainer();
 
     ShapeOutsideInfo::removeInfo(*this);
 
@@ -150,7 +151,7 @@ void LayoutBox::removeFloatingOrPositionedChildFromBlockLists()
     }
 
     if (isOutOfFlowPositioned())
-        LayoutBlock::removePositionedObject(this);
+        removeFromPositionedContainer();
 }
 
 void LayoutBox::styleWillChange(StyleDifference diff, const ComputedStyle& newStyle)
@@ -208,11 +209,10 @@ void LayoutBox::styleDidChange(StyleDifference diff, const ComputedStyle* oldSty
 
     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.
@@ -4895,4 +4895,50 @@ void LayoutBox::clearPreviousPaintInvalidationRects()
         scrollableArea->clearPreviousPaintInvalidationRects();
 }
 
+void LayoutBox::setPositionedContainer(LayoutBlock* container)
+{
+    ASSERT(!container || !positionedContainer());
+    if (!container && !m_rareData)
+        return;
+    ensureRareData().m_positionedContainer = container;
+}
+
+void LayoutBox::removeFromPositionedContainer()
+{
+    if (!positionedContainer())
+        return;
+
+    ASSERT(positionedContainer()->positionedObjects()->contains(this));
+    positionedContainer()->removePositionedObject(this);
+    // The above call should call this object's setPositionedContainer(nullptr).
+    ASSERT(!positionedContainer());
+}
+
+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