Treat implicit height on positioned objects as non-auto

third_party/WebKit/Source/core/layout/LayoutBoxModelObject.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 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. 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 474 matching lines @@
 
 void LayoutBoxModelObject::updateFromStyle()
 {
     const ComputedStyle& styleToUse = styleRef();
     setHasBoxDecorationBackground(styleToUse.hasBoxDecorationBackground());
     setInline(styleToUse.isDisplayInlineType());
     setPositionState(styleToUse.position());
     setHorizontalWritingMode(styleToUse.isHorizontalWritingMode());
 }
 
+static inline bool isOutOfFlowPositionedWithImplicitHeight(const LayoutBoxModelObject* child)
+{
+    return child->isOutOfFlowPositioned() && !child->style()->logicalTop().isAuto() && !child->style()->logicalBottom().isAuto();
+}
+
 LayoutBlock* LayoutBoxModelObject::containingBlockForAutoHeightDetection(Length logicalHeight) const
 {
     // For percentage heights: The percentage is calculated with respect to the height of the generated box's
     // containing block. If the height of the containing block is not specified explicitly (i.e., it depends
     // on content height), and this element is not absolutely positioned,  the used height is calculated
     // as if 'auto' was specified.
     if (!logicalHeight.hasPercent() || isOutOfFlowPositioned())
         return nullptr;
 
     // Anonymous block boxes are ignored when resolving percentage values that would refer to it:
     // the closest non-anonymous ancestor box is used instead.
     LayoutBlock* cb = containingBlock();
     while (cb->isAnonymous())
         cb = cb->containingBlock();
 
     // Matching LayoutBox::percentageLogicalHeightIsResolvableFromBlock() by
     // ignoring table cell's attribute value, where it says that table cells violate
     // what the CSS spec says to do with heights. Basically we
     // don't care if the cell specified a height or not.
     if (cb->isTableCell())
         return nullptr;
 
     // Match LayoutBox::availableLogicalHeightUsing by special casing
     // the layout view. The available height is taken from the frame.
     if (cb->isLayoutView())
         return nullptr;
 
-    if (cb->isOutOfFlowPositioned() && !cb->style()->logicalTop().isAuto() && !cb->style()->logicalBottom().isAuto())
+    if (isOutOfFlowPositionedWithImplicitHeight(cb))
         return nullptr;
 
     return cb;
 }
 
 bool LayoutBoxModelObject::hasAutoHeightOrContainingBlockWithAutoHeight(bool checkingContainingBlock) const
 {
     const LayoutBox* thisBox = isBox() ? toLayoutBox(this) : nullptr;
     Length logicalHeightLength = style()->logicalHeight();
     LayoutBlock* cb = containingBlockForAutoHeightDetection(logicalHeightLength);
     if (logicalHeightLength.hasPercent() && cb && isBox())
         cb->addPercentHeightDescendant(const_cast<LayoutBox*>(toLayoutBox(this)));
     if (thisBox && thisBox->isFlexItem()) {
         LayoutFlexibleBox& flexBox = toLayoutFlexibleBox(*parent());
         if (flexBox.childLogicalHeightForPercentageResolution(*thisBox) != LayoutUnit(-1))
             return false;
     }
     if (thisBox && thisBox->isGridItem()) {
         if (checkingContainingBlock && thisBox->hasOverrideLogicalContentHeight())
             return false;
         if (!checkingContainingBlock && thisBox->hasOverrideContainingBlockLogicalHeight())
             return false;
     }
-    if (logicalHeightLength.isAuto())
+    if (logicalHeightLength.isAuto() && !isOutOfFlowPositionedWithImplicitHeight(this))
         return true;
 
     if (document().inQuirksMode())
         return false;
 
     // If the height of the containing block computes to 'auto', then it hasn't been 'specified explicitly'.
     if (cb)
         return cb->hasAutoHeightOrContainingBlockWithAutoHeight(true);
     return false;
 }
@@ skipping 548 matching lines @@
     if (rootElementStyle->hasBackground())
         return false;
 
     if (node() != document().firstBodyElement())
         return false;
 
     return true;
 }
 
 } // namespace blink