Don't allow position:sticky for table columns.

Source/core/css/resolver/StyleAdjuster.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2004-2005 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2006, 2007 Nicholas Shanks (webkit@nickshanks.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013 Apple Inc. All rights reserved.
  * Copyright (C) 2007 Alexey Proskuryakov <ap@webkit.org>
  * Copyright (C) 2007, 2008 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (c) 2011, Code Aurora Forum. All rights reserved.
  * Copyright (C) Research In Motion Limited 2011. All rights reserved.
@@ skipping 242 matching lines @@
 
         // Absolute/fixed positioned elements, floating elements and the document element need block-like outside display.
         if (style->hasOutOfFlowPosition() || style->isFloating() || (e && e->document().documentElement() == e))
             style->setDisplay(equivalentBlockDisplay(style->display(), style->isFloating(), !m_useQuirksModeStyles));
 
         // FIXME: Don't support this mutation for pseudo styles like first-letter or first-line, since it's not completely
         // clear how that should work.
         if (style->display() == INLINE && style->styleType() == NOPSEUDO && style->writingMode() != parentStyle->writingMode())
             style->setDisplay(INLINE_BLOCK);
 
-        // After performing the display mutation, check table rows. We do not honor position:relative or position:sticky on
-        // table rows or cells. This has been established for position:relative in CSS2.1 (and caused a crash in containingBlock()
+        // After performing the display mutation, check table rows. We do not honor position:relativetable rows or cells.

[Julien - ping for review, 2014/03/13 01:08:06]

Nit: Space after the colon.

[ostap, 2014/03/13 15:46:45]

Done.

+        // This has been established for position:relative in CSS2.1 (and caused a crash in containingBlock()
         // on some sites).
         if ((style->display() == TABLE_HEADER_GROUP || style->display() == TABLE_ROW_GROUP
             || style->display() == TABLE_FOOTER_GROUP || style->display() == TABLE_ROW)
             && style->position() == RelativePosition)
             style->setPosition(StaticPosition);
 
+        // Do not allow position:sticky for table columns and column groups because table columns

[Julien - ping for review, 2014/03/13 01:08:06]

Same nit.

[ostap, 2014/03/13 15:46:45]

Done.

+        // don't have RenderLayer

[Julien - ping for review, 2014/03/13 01:08:06]

I don't think this is a good explanation. A better one is that we can't support
position: sticky with our current code as we only do background painting through
columns / column groups. The fact that we don't want a RenderLayer is a
consequence of that, not a cause.

[ostap, 2014/03/13 15:46:45]

Done.

+        if ((style->display() == TABLE_COLUMN_GROUP || style->display() == TABLE_COLUMN)
+            && style->position() == StickyPosition)
+            style->setPosition(StaticPosition);
+
         // writing-mode does not apply to table row groups, table column groups, table rows, and table columns.
         // FIXME: Table cells should be allowed to be perpendicular or flipped with respect to the table, though.
         if (style->display() == TABLE_COLUMN || style->display() == TABLE_COLUMN_GROUP || style->display() == TABLE_FOOTER_GROUP
             || style->display() == TABLE_HEADER_GROUP || style->display() == TABLE_ROW || style->display() == TABLE_ROW_GROUP
             || style->display() == TABLE_CELL)
             style->setWritingMode(parentStyle->writingMode());
 
         // FIXME: Since we don't support block-flow on flexible boxes yet, disallow setting
         // of block-flow to anything other than TopToBottomWritingMode.
         // https://bugs.webkit.org/show_bug.cgi?id=46418 - Flexible box support.
@@ skipping 160 matching lines @@
     if (prop.isNamedGridArea() && !map.contains(prop.namedGridLine())) \
         style->setGrid##Prop(GridPosition());
 
     CLEAR_UNKNOWN_NAMED_AREA(columnStartPosition, ColumnStart);
     CLEAR_UNKNOWN_NAMED_AREA(columnEndPosition, ColumnEnd);
     CLEAR_UNKNOWN_NAMED_AREA(rowStartPosition, RowStart);
     CLEAR_UNKNOWN_NAMED_AREA(rowEndPosition, RowEnd);
 }
 
 }