Reland of Improve how the column balancer handles top margins on floats.

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
@@ skipping 688 matching lines @@
                    m_frameRect.height().toFloat());
 }
 
 void LayoutBox::updateLayerTransformAfterLayout() {
   // Transform-origin depends on box size, so we need to update the layer
   // transform after layout.
   if (hasLayer())
     layer()->updateTransformationMatrix();
 }
 
-LayoutUnit LayoutBox::logicalHeightIncludingOverflow() const {
-  if (!m_overflow)
+LayoutUnit LayoutBox::logicalHeightWithVisibleOverflow() const {
+  if (!m_overflow || hasOverflowClip())
     return logicalHeight();
   LayoutRect overflow = layoutOverflowRect();
   if (style()->isHorizontalWritingMode())
     return overflow.maxY();
   return overflow.maxX();
 }
 
 LayoutUnit LayoutBox::constrainLogicalWidthByMinMax(LayoutUnit logicalWidth,
                                                     LayoutUnit availableWidth,
                                                     LayoutBlock* cb) const {
@@ skipping 3984 matching lines @@
 }
 
 void LayoutBox::updateFragmentationInfoForChild(LayoutBox& child) {
   LayoutState* layoutState = view()->layoutState();
   DCHECK(layoutState->isPaginated());
   child.setOffsetToNextPage(LayoutUnit());
   if (!pageLogicalHeightForOffset(child.logicalTop()))
     return;
 
   LayoutUnit logicalTop = child.logicalTop();
-  LayoutUnit logicalHeight = child.logicalHeightIncludingOverflow();
+  LayoutUnit logicalHeight = child.logicalHeightWithVisibleOverflow();
   LayoutUnit spaceLeft =
       pageRemainingLogicalHeightForOffset(logicalTop, AssociateWithLatterPage);
   if (spaceLeft < logicalHeight)
     child.setOffsetToNextPage(spaceLeft);
 }
 
 bool LayoutBox::childNeedsRelayoutForPagination(const LayoutBox& child) const {
   // TODO(mstensho): Should try to get this to work for floats too, instead of
   // just marking and bailing here.
   if (child.isFloating())
     return true;
   LayoutUnit logicalTop = child.logicalTop();
   // Figure out if we really need to force re-layout of the child. We only need
   // to do this if there's a chance that we need to recalculate pagination
   // struts inside.
   if (LayoutUnit pageLogicalHeight = pageLogicalHeightForOffset(logicalTop)) {
-    LayoutUnit logicalHeight = child.logicalHeightIncludingOverflow();
+    LayoutUnit logicalHeight = child.logicalHeightWithVisibleOverflow();
     LayoutUnit remainingSpace = pageRemainingLogicalHeightForOffset(
         logicalTop, AssociateWithLatterPage);
     if (child.offsetToNextPage()) {
       // We need to relayout unless we're going to break at the exact same
       // location as before.
       if (child.offsetToNextPage() != remainingSpace)
         return true;
     } else if (logicalHeight > remainingSpace) {
       // Last time we laid out this child, we didn't need to break, but now we
       // have to. So we need to relayout.
@@ skipping 895 matching lines @@
   LayoutRect rect = frameRect();
 
   LayoutBlock* block = containingBlock();
   if (block)
     block->adjustChildDebugRect(rect);
 
   return rect;
 }
 
 }  // namespace blink