LayoutBox (not LayoutBlock) is the common base for floats and out-of-flow objects.

third_party/WebKit/Source/core/layout/LayoutBlock.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 300 matching lines @@
         LayoutObject* sibling = child->previousSibling();
         parentBlockFlow->moveChildTo(this, child, firstChild(), false);
         child = sibling;
     }
 }
 
 void LayoutBlock::styleDidChange(StyleDifference diff, const ComputedStyle* oldStyle)
 {
     LayoutBox::styleDidChange(diff, oldStyle);
 
-    if (isFloatingOrOutOfFlowPositioned() && oldStyle && !oldStyle->isFloating() && !oldStyle->hasOutOfFlowPosition() && parent() && parent()->isLayoutBlockFlow())
-        toLayoutBlockFlow(parent())->childBecameFloatingOrOutOfFlow(this);
-
     const ComputedStyle& newStyle = styleRef();
 
     if (oldStyle && parent()) {
         if (oldStyle->position() != newStyle.position() && newStyle.position() != StaticPosition) {
             // Remove our absolute and fixed positioned descendants from their new containing block,
             // in case containingBlock() changes by the change to the position property.
             // See styleWillChange() for other cases.
             if (LayoutBlock* cb = containingBlock())
                 cb->removePositionedObjects(this, NewContainingBlock);
         }
@@ skipping 1909 matching lines @@
         for (TrackedLayoutBoxListHashSet::const_iterator it = positionedDescendantSet->begin(); it != end; ++it) {
             LayoutBox* currBox = *it;
             ASSERT(!currBox->needsLayout());
         }
     }
 }
 
 #endif
 
 } // namespace blink