RenderBlock::isSelfCollapsingBlock() should only be used when an object does not require layout.

Source/core/rendering/RenderObject.cpp

Index: Source/core/rendering/RenderObject.cpp
diff --git a/Source/core/rendering/RenderObject.cpp b/Source/core/rendering/RenderObject.cpp
index 77b99b30e0ff38e48b956bd8632a847308beca28..22f2dad43404bc18048464ea502c3a950a56ce29 100644
--- a/Source/core/rendering/RenderObject.cpp
+++ b/Source/core/rendering/RenderObject.cpp
@@ -74,6 +74,7 @@
 #include "core/rendering/RenderTableCell.h"
 #include "core/rendering/RenderTableCol.h"
 #include "core/rendering/RenderTableRow.h"
+#include "core/rendering/RenderTextControlPlaceholder.h"
 #include "core/rendering/RenderTheme.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/style/ContentData.h"
@@ -161,6 +162,9 @@ RenderObject* RenderObject::createObject(Element* element, RenderStyle* style)
         return image;
     }
 
+    if (element->shadowPseudoId() == "-webkit-input-placeholder")

[ojan, 2014/01/28 23:59:48]

esprehn nagged me that we really shouldn't be adding special-cases like this if
we can at all avoid them. I think we should revert this part of the patch, which
I realize means putting back in the FIXME in
RenderBlock::isSelfCollapsingBlock().

+        return new RenderTextControlPlaceholder(element);
+
     if (element->hasTagName(rubyTag)) {
         if (style->display() == INLINE)
             return new RenderRubyAsInline(element);