Don't add floats on clean lines to new lineboxes

Source/core/layout/LayoutBlockFlowLine.cpp

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2003, 2004, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All right reserved.
  * Copyright (C) 2010 Google Inc. 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
  * version 2 of the License, or (at your option) any later version.
  *
@@ skipping 882 matching lines @@
                 FloatingObjectSetIterator it = floatingObjectSet.begin();
                 FloatingObjectSetIterator end = floatingObjectSet.end();
                 if (layoutState.lastFloat()) {
                     FloatingObjectSetIterator lastFloatIterator = floatingObjectSet.find(layoutState.lastFloat());
                     ASSERT(lastFloatIterator != end);
                     ++lastFloatIterator;
                     it = lastFloatIterator;
                 }
                 for (; it != end; ++it) {
                     FloatingObject& floatingObject = *it->get();
+                    // If we've reached the start of clean lines any remaining floating children belong to them.
+                    // We don't care about the 'last float' mechanism once we're in clean lines so it's ok to let it get set below.
+                    if (floatingObject.layoutObject() == cleanLineStart.object())
+                        break;
                     appendFloatingObjectToLastLine(floatingObject);
                     ASSERT(floatingObject.layoutObject() == layoutState.floats()[layoutState.floatIndex()].object);
                     // If a float's geometry has changed, give up on syncing with clean lines.
                     if (layoutState.floats()[layoutState.floatIndex()].rect != floatingObject.frameRect())
                         checkForEndLineMatch = false;
                     layoutState.setFloatIndex(layoutState.floatIndex() + 1);
                 }
                 layoutState.setLastFloat(!floatingObjectSet.isEmpty() ? floatingObjectSet.last().get() : 0);
             }
         }
@@ skipping 1100 matching lines @@
     LayoutUnit logicalLeft = logicalLeftOffsetForLine(logicalHeight(), false);
     LayoutUnit availableLogicalWidth = logicalRightOffsetForLine(logicalHeight(), false) - logicalLeft;
     updateLogicalWidthForAlignment(textAlign, 0, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);
 
     if (!style()->isLeftToRightDirection())
         return logicalWidth() - logicalLeft;
     return logicalLeft;
 }
 
 }