Implement lazy block layout prototype behind a runtime flag.

Source/core/rendering/RenderObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 44 matching lines @@
 #include "core/rendering/RenderDeprecatedFlexibleBox.h"
 #include "core/rendering/RenderFlexibleBox.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderGrid.h"
 #include "core/rendering/RenderImage.h"
 #include "core/rendering/RenderImageResourceStyleImage.h"
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderLayerBacking.h"
 #include "core/rendering/RenderLayerCompositor.h"
+#include "core/rendering/RenderLazyBlock.h"
 #include "core/rendering/RenderListItem.h"
 #include "core/rendering/RenderMultiColumnBlock.h"
 #include "core/rendering/RenderNamedFlowThread.h"
 #include "core/rendering/RenderRegion.h"
 #include "core/rendering/RenderRuby.h"
 #include "core/rendering/RenderRubyText.h"
 #include "core/rendering/RenderScrollbarPart.h"
 #include "core/rendering/RenderTableCaption.h"
 #include "core/rendering/RenderTableCell.h"
 #include "core/rendering/RenderTableCol.h"
@@ skipping 127 matching lines @@
         return new (arena) RenderTableCaption(element);
     case BOX:
     case INLINE_BOX:
         return new (arena) RenderDeprecatedFlexibleBox(element);
     case FLEX:
     case INLINE_FLEX:
         return new (arena) RenderFlexibleBox(element);
     case GRID:
     case INLINE_GRID:
         return new (arena) RenderGrid(element);
+    case LAZY_BLOCK:
+        return new (arena) RenderLazyBlock(element);
     }
 
     return 0;
 }
 
 DEFINE_DEBUG_ONLY_GLOBAL(WTF::RefCountedLeakCounter, renderObjectCounter, ("RenderObject"));
 
 RenderObject::RenderObject(Node* node)
     : CachedImageClient()
     , m_style(0)
@@ skipping 2944 matching lines @@
 {
     if (object1) {
         const WebCore::RenderObject* root = object1;
         while (root->parent())
             root = root->parent();
         root->showRenderTreeAndMark(object1, "*", object2, "-", 0);
     }
 }
 
 #endif