[css-grid] Fix indefinite height detection

third_party/WebKit/Source/core/layout/LayoutBlock.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Apple 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
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
@@ skipping 208 matching lines @@
     LayoutUnit startOffsetForContent() const { return style()->isLeftToRightDirection() ? logicalLeftOffsetForContent() : logicalWidth() - logicalRightOffsetForContent(); }
     LayoutUnit endOffsetForContent() const { return !style()->isLeftToRightDirection() ? logicalLeftOffsetForContent() : logicalWidth() - logicalRightOffsetForContent(); }
 
     virtual LayoutUnit logicalLeftSelectionOffset(const LayoutBlock* rootBlock, LayoutUnit position) const;
     virtual LayoutUnit logicalRightSelectionOffset(const LayoutBlock* rootBlock, LayoutUnit position) const;
 
 #if ENABLE(ASSERT)
     void checkPositionedObjectsNeedLayout();
 #endif
 
+    LayoutUnit availableLogicalHeightForPercentageComputation() const;

[cbiesinger, 2016/08/25 21:50:23]

Upon re-reading this patch, I really think this needs a comment that you need to
call this function on the right containing block --
computePercentageLogicalHeight has the function to find the containing block,
but you did not move it to the new function.

[Manuel Rego, 2016/08/29 11:08:54]

We want to be able to call this function directly on any block,
that's why it doesn't have the loop to find the right containing block.
It's true that we've an issue now that we can call this from anywhere
(due to hasDefiniteLogicalHeight()).

I've added a check using skipContainingBlockForPercentHeightCalculation(),
it seems that if this is true we can consider that the element has an indefinite
height.
Basically they're mostly anonymous blocks that are skipped
during percentage height calculations, so I guess it's fine to consider
they have an indefinite height for the purpose of hasDefiniteLogicalHeight().

+    bool hasDefiniteLogicalHeight() const;

[cbiesinger, 2016/08/25 21:50:22]

..and that previous point makes me think this function might not be correct?

+
 protected:
     bool recalcNormalFlowChildOverflowIfNeeded(LayoutObject*);
     bool recalcPositionedDescendantsOverflowAfterStyleChange();
 public:
     virtual bool recalcChildOverflowAfterStyleChange();
     bool recalcOverflowAfterStyleChange();
 
     // An example explaining layout tree structure about first-line style:
     // <style>
     //   #enclosingFirstLineStyleBlock::first-line { ... }
@@ skipping 179 matching lines @@
     // This is necessary for now for interoperability between the old and new
     // layout code. Primarily for calling layoutPositionedObjects at the moment.
     friend class NGBox;
 };
 
 DEFINE_LAYOUT_OBJECT_TYPE_CASTS(LayoutBlock, isLayoutBlock());
 
 } // namespace blink
 
 #endif // LayoutBlock_h