[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 1242 matching lines @@
     // (b) are a table,
     // (c) have border/padding,
     // (d) have a min-height
     // (e) have specified that one of our margins can't collapse using a CSS extension
     // (f) establish a new block formatting context.
 
     // The early exit must be done before we check for clean layout.
     // We should be able to give a quick answer if the box is a relayout boundary.
     // Being a relayout boundary implies a block formatting context, and also
     // our internal layout shouldn't affect our container in any way.
-    if (createsBlockFormattingContext())
+    if (createsNewFormattingContext())
         return false;
 
     // Placeholder elements are not laid out until the dimensions of their parent text control are known, so they
     // don't get layout until their parent has had layout - this is unique in the layout tree and means
     // when we call isSelfCollapsingBlock on them we find that they still need layout.
     ASSERT(!needsLayout() || (node() && node()->isElementNode() && toElement(node())->shadowPseudoId() == "-webkit-input-placeholder"));
 
     if (logicalHeight() > 0
         || isTable() || borderAndPaddingLogicalHeight()
         || style()->logicalMinHeight().isPositive()
@@ skipping 237 matching lines @@
 void RenderBlock::addVisualOverflowFromTheme()
 {
     if (!style()->hasAppearance())
         return;
 
     IntRect inflatedRect = pixelSnappedBorderBoxRect();
     RenderTheme::theme().adjustPaintInvalidationRect(this, inflatedRect);
     addVisualOverflow(inflatedRect);
 }
 
-bool RenderBlock::createsBlockFormattingContext() const
+bool RenderBlock::createsNewFormattingContext() const
 {
     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() || isGridItem();
 }
 
 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