Introduce markChildForPaginationRelayoutIfNeeded().

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 4035 matching lines @@
 {
     if (PaintLayerScrollableArea* scrollableArea = this->getScrollableArea()) {
         if (scrollableArea->hasHorizontalScrollbar() && !scrollableArea->layerForHorizontalScrollbar())
             return true;
         if (scrollableArea->hasVerticalScrollbar() && !scrollableArea->layerForVerticalScrollbar())
             return true;
     }
     return false;
 }
 
-void LayoutBox::markForPaginationRelayoutIfNeeded(SubtreeLayoutScope& layoutScope)
+void LayoutBox::markChildForPaginationRelayoutIfNeeded(LayoutBox& child, SubtreeLayoutScope& layoutScope)
 {
-    ASSERT(!needsLayout());
-    // If fragmentation height has changed, we need to lay out. No need to enter the layoutObject if it
-    // is childless, though.
-    if (view()->layoutState()->pageLogicalHeightChanged() && slowFirstChild())
-        layoutScope.setChildNeedsLayout(this);
+    DCHECK(!child.needsLayout());
+    LayoutState* layoutState = view()->layoutState();
+    if (!layoutState->isPaginated())
+        return;
+
+    if (layoutState->pageLogicalHeightChanged() || (layoutState->pageLogicalHeight() && layoutState->pageLogicalOffset(child, child.logicalTop()) != child.pageLogicalOffset()))
+        layoutScope.setChildNeedsLayout(&child);
 }
 
 void LayoutBox::markOrthogonalWritingModeRoot()
 {
     ASSERT(frameView());
     frameView()->addOrthogonalWritingModeRoot(*this);
 }
 
 void LayoutBox::unmarkOrthogonalWritingModeRoot()
 {
@@ skipping 806 matching lines @@
     LayoutRect rect = frameRect();
 
     LayoutBlock* block = containingBlock();
     if (block)
         block->adjustChildDebugRect(rect);
 
     return rect;
 }
 
 } // namespace blink