[New Multicolumn] balancer confused by content with top margins.

Source/core/rendering/LayoutState.cpp

Index: Source/core/rendering/LayoutState.cpp
diff --git a/Source/core/rendering/LayoutState.cpp b/Source/core/rendering/LayoutState.cpp
index e9cb94b10e2472b672b4caf5e24b973d10338639..7d2894c449f94b7ea5ec282e796ad63be46a4ad5 100644
--- a/Source/core/rendering/LayoutState.cpp
+++ b/Source/core/rendering/LayoutState.cpp
@@ -119,7 +119,7 @@ LayoutState::LayoutState(LayoutState* prev, RenderBox& renderer, const LayoutSiz
 #endif
     }
 
-    m_isPaginated = m_pageLogicalHeight || m_columnInfo || renderer.isRenderFlowThread();
+    m_isPaginated = m_pageLogicalHeight || m_columnInfo || renderer.flowThreadContainingBlock();

[abucur, 2014/03/25 10:02:36]

I think there's a chance you are breaking unsplittable content here such as
images / scrollable containers. m_isPaginated will be true for all the renderers
inside a flow thread because the inherited page height doesn't control this flag
any more. A couple of lines above, the page logical height is set to 0 for
unsplittable content but m_isPaginated will be true because
flowThreadContainingBlock() will be non-null.

Maybe you can group this isPaginated/isNotPaginated logic into a helper function
that should handle all the situations.

[mstensho (USE GERRIT), 2014/03/26 09:56:25]

Done.

 
     // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if present.
 }