Absolute positioned child with percent should include containing block padding

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 1588 matching lines @@
     // We need to see if margins on either the start side or the end side can contain the floats in question. If they can,
     // then just using the line width is inaccurate. In the case where a float completely fits, we don't need to use the line
     // offset at all, but can instead push all the way to the content edge of the containing block. In the case where the float
     // doesn't fit, we can use the line offset, but we need to grow it by the margin to reflect the fact that the margin was
     // "consumed" by the float. Negative margins aren't consumed by the float, and so we ignore them.
     width += portionOfMarginNotConsumedByFloat(childMarginStart, startOffsetForContent, startOffsetForLine);
     width += portionOfMarginNotConsumedByFloat(childMarginEnd, endOffsetForContent, endOffsetForLine);
     return width;
 }
 
+LayoutUnit LayoutBox::containingBlockLogicalWidthForGetComputedStyle() const
+{
+    if (hasOverrideContainingBlockLogicalWidth())
+        return overrideContainingBlockContentLogicalWidth();
+
+    if (!isPositioned())
+        return containingBlockLogicalWidthForContent();
+
+    LayoutBoxModelObject* cb = toLayoutBoxModelObject(container());

[esprehn, 2016/04/14 18:43:09]

why is container correct vs containingBlock?

[Deokjin Kim, 2016/04/20 13:42:09]

I think this issue is caused by the difference between clientLogicalWidth() and
availableLogicalWidth(). clientLogicalWidth() includes padding, but
availableLogicalWidth() doesn't include padding.

+    LayoutUnit width = containingBlockLogicalWidthForPositioned(cb);
+    if (styleRef().position() != AbsolutePosition)
+        width -= cb->paddingLogicalWidth();
+    return width;
+}
+
 LayoutUnit LayoutBox::containingBlockLogicalHeightForGetComputedStyle() const
 {
     if (hasOverrideContainingBlockLogicalHeight())
         return overrideContainingBlockContentLogicalHeight();
 
     if (!isPositioned())
         return containingBlockLogicalHeightForContent(ExcludeMarginBorderPadding);
 
     LayoutBoxModelObject* cb = toLayoutBoxModelObject(container());
     LayoutUnit height = containingBlockLogicalHeightForPositioned(cb);
@@ skipping 3118 matching lines @@
 
 void LayoutBox::clearPercentHeightDescendants()
 {
     for (LayoutObject* curr = slowFirstChild(); curr; curr = curr->nextInPreOrder(this)) {
         if (curr->isBox())
             toLayoutBox(curr)->removeFromPercentHeightContainer();
     }
 }
 
 } // namespace blink