Remove multicol special-cases from invalidation and the pre-paint tree walk

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

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc.
  *               All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved.
  *               (http://www.torchmobile.com/)
@@ skipping 601 matching lines @@
 }
 
 PaintLayer* LayoutObject::paintingLayer() const {
   for (const LayoutObject* current = this; current;
        // Use containingBlock instead of paintInvalidationParent for floating
        // object to omit any self-painting layers of inline objects that don't
        // paint the floating object.
        current = current->isFloating() ? current->containingBlock()
                                        : current->paintInvalidationParent()) {
     if (current->hasLayer() &&
-        toLayoutBoxModelObject(current)->layer()->isSelfPaintingLayer())
+        toLayoutBoxModelObject(current)->layer()->isSelfPaintingLayer()) {
       return toLayoutBoxModelObject(current)->layer();
+    } else if (current->isColumnSpanAll()) {
+      // Column spanners paint through their multicolumn containers which can
+      // be accessed through the associated out-of-flow placeholder's parent.
+      current = current->spannerPlaceholder();
+    }
   }
   // TODO(crbug.com/365897): we should get rid of detached layout subtrees, at
   // which point this code should not be reached.
   return nullptr;
 }
 
 bool LayoutObject::scrollRectToVisible(const LayoutRect& rect,
                                        const ScrollAlignment& alignX,
                                        const ScrollAlignment& alignY,
                                        ScrollType scrollType,
@@ skipping 549 matching lines @@
   invalidatePaintOfSubtreesIfNeeded(newPaintInvalidationState);
 
   clearPaintInvalidationFlags();
 }
 
 DISABLE_CFI_PERF
 void LayoutObject::invalidatePaintOfSubtreesIfNeeded(
     const PaintInvalidationState& childPaintInvalidationState) {
   DCHECK(!RuntimeEnabledFeatures::slimmingPaintInvalidationEnabled());
 
-  for (LayoutObject* child = slowFirstChild(); child;
-       child = child->nextSibling()) {
-    // Column spanners are invalidated through their placeholders. See
-    // LayoutMultiColumnSpannerPlaceholder::invalidatePaintOfSubtreesIfNeeded().
-    if (child->isColumnSpanAll())
-      continue;
+  for (auto* child = slowFirstChild(); child; child = child->nextSibling())
     child->invalidateTreeIfNeeded(childPaintInvalidationState);
-  }
 }
 
 LayoutRect LayoutObject::selectionRectInViewCoordinates() const {
   LayoutRect selectionRect = localSelectionRect();
   if (!selectionRect.isEmpty())
     mapToVisualRectInAncestorSpace(view(), selectionRect);
   return selectionRect;
 }
 
 PaintInvalidationReason LayoutObject::invalidatePaintIfNeeded(
@@ skipping 1336 matching lines @@
 
   if (isFloating())
     return containingBlock(ancestor, ancestorSkipped, filterSkipped);
 
   return parent();
 }
 
 inline LayoutObject* LayoutObject::paintInvalidationParent() const {
   if (isLayoutView())
     return LayoutAPIShim::layoutObjectFrom(frame()->ownerLayoutItem());
-  if (isColumnSpanAll())
-    return spannerPlaceholder();
   return parent();
 }
 
 LayoutObject* LayoutObject::slowPaintInvalidationParentForTesting() const {
   return paintInvalidationParent();
 }
 
 bool LayoutObject::isSelectionBorder() const {
   SelectionState st = getSelectionState();
   return st == SelectionStart || st == SelectionEnd || st == SelectionBoth;
@@ skipping 971 matching lines @@
     const blink::LayoutObject* root = object1;
     while (root->parent())
       root = root->parent();
     root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
   } else {
     WTFLogAlways("%s", "Cannot showLayoutTree. Root is (nil)");
   }
 }
 
 #endif