[CSS Grid Layout] Grid items must set a new formatting context.

Source/core/rendering/RenderBlock.cpp

 /*
  * 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, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. 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
@@ skipping 1500 matching lines @@
 void RenderBlock::addVisualOverflowFromTheme()
 {
     if (!style()->hasAppearance())
         return;
 
     IntRect inflatedRect = pixelSnappedBorderBoxRect();
     RenderTheme::theme().adjustPaintInvalidationRect(this, inflatedRect);
     addVisualOverflow(inflatedRect);
 }
 
 bool RenderBlock::createsBlockFormattingContext() const

[Julien - ping for review, 2014/11/11 16:27:01]

This function is deeply misnamed as most elements listed in it don't establish
*block* formatting contexts. Let's rename it to createNewFormattingContext for
clarity.

That would also help explain that we can have other impact from this change
(like float not protruding into the next grid item, which we should test btw).

[jfernandez, 2014/11/12 13:22:44]

Done.
Added a new layout tests for that issue.

 {
     return isInlineBlockOrInlineTable() || isFloatingOrOutOfFlowPositioned() || hasOverflowClip() || isFlexItemIncludingDeprecated()
-        || style()->specifiesColumns() || isRenderFlowThread() || isTableCell() || isTableCaption() || isFieldset() || isWritingModeRoot() || isDocumentElement() || style()->columnSpan();
+        || style()->specifiesColumns() || isRenderFlowThread() || isTableCell() || isTableCaption() || isFieldset() || isWritingModeRoot()
+        || isDocumentElement() || style()->columnSpan() || containingBlock()->isRenderGrid();

[Manuel Rego, 2014/11/11 13:54:22]

It think that you could define something similar to:
RenderBox::isFlexItemIncludingDeprecated()

It might be useful in other places in the future.

[Julien - ping for review, 2014/11/11 16:27:01]

I don't have a preference about adding a helper function.

However I think we will want to use parent() instead of containingBlock() as
positioned elements create a new formatting context anyway. Also parent() is a
lot cheaper.

[jfernandez, 2014/11/12 13:22:44]

Done.

[jfernandez, 2014/11/12 13:22:44]

Done.

 }
 
 void RenderBlock::updateBlockChildDirtyBitsBeforeLayout(bool relayoutChildren, RenderBox* child)
 {
     // FIXME: Technically percentage height objects only need a relayout if their percentage isn't going to be turned into
     // an auto value. Add a method to determine this, so that we can avoid the relayout.
     if (relayoutChildren || (child->hasRelativeLogicalHeight() && !isRenderView()))
         child->setChildNeedsLayout(MarkOnlyThis);
 
     // If relayoutChildren is set and the child has percentage padding or an embedded content box, we also need to invalidate the childs pref widths.
@@ skipping 2847 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink