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

third_party/WebKit/Source/core/paint/PaintInvalidator.cpp

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "core/paint/PaintInvalidator.h"
 
 #include "core/editing/FrameSelection.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
@@ skipping 181 matching lines @@
       *context.paintInvalidationContainer, point);
 
   return LayoutPoint(point);
 }
 
 void PaintInvalidator::updatePaintingLayer(const LayoutObject& object,
                                            PaintInvalidatorContext& context) {
   if (object.hasLayer() &&
       toLayoutBoxModelObject(object).hasSelfPaintingLayer()) {
     context.paintingLayer = toLayoutBoxModelObject(object).layer();
-  } else if (object.isFloating() && !object.parent()->isLayoutBlock()) {
-    // See LayoutObject::paintingLayer() for specialty of floating objects.
+  } else if (object.isColumnSpanAll() ||
+             (object.isFloating() && !object.parent()->isLayoutBlock())) {
+    // See LayoutObject::paintingLayer() for the special-cases of floating under
+    // inline and multicolumn.
     context.paintingLayer = object.paintingLayer();
   }
 
   if (object.isLayoutBlockFlow() && toLayoutBlockFlow(object).containsFloats())
     context.paintingLayer->setNeedsPaintPhaseFloat();
 
   if (object == context.paintingLayer->layoutObject())
     return;
 
   if (object.styleRef().hasOutline())
@@ skipping 237 matching lines @@
         PaintInvalidatorContext::ForcedSubtreeInvalidationRectUpdate;
 }
 
 void PaintInvalidator::processPendingDelayedPaintInvalidations() {
   for (auto target : m_pendingDelayedPaintInvalidations)
     target->getMutableForPainting().setShouldDoFullPaintInvalidation(
         PaintInvalidationDelayedFull);
 }
 
 }  // namespace blink