[New Multicolumn] Support for block direction margins on spanners.

Source/core/rendering/RenderBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 1049 matching lines @@
             continue;
         }
         if (child->isFloating()) {
             insertFloatingObject(*child);
             adjustFloatingBlock(marginInfo);
             continue;
         }
         if (child->isColumnSpanAll()) {
             // This is not the containing block of the spanner. The spanner's placeholder will lay
             // it out in due course. For now we just need to consult our flow thread, so that the
-            // columns (if any) preceding and following the spanner are laid out correctly.
+            // columns (if any) preceding and following the spanner are laid out correctly. But
+            // first we apply the pending margin, so that it's taken into consideration and doesn't
+            // end up on the other side of the spanner.
+            setLogicalHeight(logicalHeight() + marginInfo.margin());
+            marginInfo.clearMargin();
+
             LayoutUnit adjustment = flowThreadContainingBlock()->skipColumnSpanner(child, offsetFromLogicalTopOfFirstPage() + logicalHeight());
             setLogicalHeight(logicalHeight() + adjustment);
             continue;
         }
 
         // Lay out the child.
         layoutBlockChild(*child, marginInfo, previousFloatLogicalBottom);
         lastNormalFlowChild = child;
     }
 
@@ skipping 389 matching lines @@
     RenderBlockFlow* childBlockFlow = toRenderBlockFlow(&child);
     if (childBlockFlow->childrenInline() || childBlockFlow->isWritingModeRoot())
         return;
 
     MarginInfo childMarginInfo(childBlockFlow, childBlockFlow->borderBefore() + childBlockFlow->paddingBefore(), childBlockFlow->borderAfter() + childBlockFlow->paddingAfter());
     if (!childMarginInfo.canCollapseMarginBeforeWithChildren())
         return;
 
     RenderBox* grandchildBox = childBlockFlow->firstChildBox();
     for ( ; grandchildBox; grandchildBox = grandchildBox->nextSiblingBox()) {
-        if (!grandchildBox->isFloatingOrOutOfFlowPositioned())
+        if (!grandchildBox->isFloatingOrOutOfFlowPositioned() && !grandchildBox->isColumnSpanAll())
             break;
     }
 
     if (!grandchildBox)
         return;
 
     // Make sure to update the block margins now for the grandchild box so that we're looking at current values.
     if (grandchildBox->needsLayout()) {
         grandchildBox->computeAndSetBlockDirectionMargins(this);
         if (grandchildBox->isRenderBlock()) {
@@ skipping 1654 matching lines @@
     FrameView* frameView = document().view();
     LayoutUnit top = (style()->position() == FixedPosition) ? 0 : frameView->scrollOffset().height();
     int visibleHeight = frameView->visibleContentRect(IncludeScrollbars).height();
     if (size().height() < visibleHeight)
         top += (visibleHeight - size().height()) / 2;
     setY(top);
     dialog->setCentered(top);
 }
 
 } // namespace blink