LayoutObject::paintInvalidationParent() to fix multicol spanner invalidation

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/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 586 matching lines @@
 
     return nullptr;
 }
 
 PaintLayer* LayoutObject::enclosingLayer() const
 {
     for (const LayoutObject* current = this; current; current = current->parent()) {
         if (current->hasLayer())
             return toLayoutBoxModelObject(current)->layer();
     }
-    // FIXME: we should get rid of detached layout subtrees, at which point this code should
-    // not be reached. crbug.com/411429
+    // TODO(crbug.com/365897): we should get rid of detached layout subtrees, at which point this code should
+    // not be reached.
     return nullptr;
 }
 
 PaintLayer* LayoutObject::paintingLayer() const
 {
-    for (const LayoutObject* current = this; current; current = current->isColumnSpanAll() ? current->containingBlock() : current->parent()) {
+    for (const LayoutObject* current = this; current; current = current->paintInvalidationParent()) {
         if (current->hasLayer() && toLayoutBoxModelObject(current)->layer()->isSelfPaintingLayer())
             return toLayoutBoxModelObject(current)->layer();
     }
+    // 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, bool makeVisibleInVisualViewport)
 {
     LayoutBox* enclosingBox = this->enclosingBox();
     if (!enclosingBox)
         return false;
 
     enclosingBox->scrollRectToVisible(rect, alignX, alignY, scrollType, makeVisibleInVisualViewport);
@@ skipping 1980 matching lines @@
                 if (filterOrReflectionSkipped && walker->hasFilterOrReflection())
                     *filterOrReflectionSkipped = true;
             }
         }
         return multicolContainer;
     }
 
     return o;
 }
 
-LayoutObject* LayoutObject::parentCrossingFrameBoundaries() const
+LayoutObject* LayoutObject::paintInvalidationParent() const
 {
-    return isLayoutView() ? frame()->ownerLayoutObject() : parent();
+    if (isLayoutView())

[chrishtr, 2016/06/13 19:49:39]

Is it important for this method to not be virtual, and hence have
type-introspection in it?

[Xianzhu, 2016/06/13 19:58:01]

Not important, but just want to make the fact that the function is crossing
frame boundary more explicit here. Also the added logic about isColumnSpanAll()
does belong here because we don't have a class for columnSpanAll.

[chrishtr, 2016/06/13 20:09:33]

It feels a little cleaner to go with virtual like various other methods, but
centralizing logic
is also nice. Up to you.

+        return frame()->ownerLayoutObject();
+    if (isColumnSpanAll())
+        return spannerPlaceholder();
+    return parent();
 }
 
 bool LayoutObject::isSelectionBorder() const
 {
     SelectionState st = getSelectionState();
     return st == SelectionStart || st == SelectionEnd || st == SelectionBoth;
 }
 
 inline void LayoutObject::clearLayoutRootIfNeeded() const
 {
@@ skipping 786 matching lines @@
         return PaintInvalidationForcedByLayout;
     case DocumentLifecycle::InCompositingUpdate:
         return PaintInvalidationCompositingUpdate;
     default:
         return PaintInvalidationFull;
     }
 }
 
 inline void LayoutObject::markAncestorsForPaintInvalidation()
 {
-    for (LayoutObject* parent = this->parentCrossingFrameBoundaries(); parent && !parent->shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState(); parent = parent->parentCrossingFrameBoundaries())
+    for (LayoutObject* parent = this->paintInvalidationParent(); parent && !parent->shouldCheckForPaintInvalidationRegardlessOfPaintInvalidationState(); parent = parent->paintInvalidationParent())
         parent->m_bitfields.setChildShouldCheckForPaintInvalidation(true);
 }
 
 void LayoutObject::setShouldInvalidateSelection()
 {
     if (!canUpdateSelectionOnRootLineBoxes())
         return;
     m_bitfields.setShouldInvalidateSelection(true);
     markAncestorsForPaintInvalidation();
     frameView()->scheduleVisualUpdateForPaintInvalidationIfNeeded();
@@ skipping 270 matching lines @@
         const blink::LayoutObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showLayoutTreeAndMark(object1, "*", object2, "-", 0);
     } else {
         fprintf(stderr, "Cannot showLayoutTree. Root is (nil)\n");
     }
 }
 
 #endif