Implement lazy block layout prototype behind a runtime flag.

Source/core/rendering/RenderView.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 21 matching lines @@
 #include "core/platform/graphics/FloatQuad.h"
 #include "core/platform/graphics/GraphicsContext.h"
 #include "core/platform/graphics/transforms/TransformState.h"
 #include "core/rendering/ColumnInfo.h"
 #include "core/rendering/FlowThreadController.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderLayerBacking.h"
 #include "core/rendering/RenderLayerCompositor.h"
+#include "core/rendering/RenderLazyBlock.h"
 #include "core/rendering/RenderNamedFlowThread.h"
 #include "core/rendering/RenderSelectionInfo.h"
 #include "core/rendering/RenderWidget.h"
 #include "core/rendering/RenderWidgetProtector.h"
 #include "core/rendering/style/StyleInheritedData.h"
 
 #if USE(3D_GRAPHICS)
 #include "core/platform/graphics/filters/custom/CustomFilterGlobalContext.h"
 #endif
 
 namespace WebCore {
 
 RenderView::RenderView(Document* document)
     : RenderBlock(document)
     , m_frameView(document->view())
     , m_selectionStart(0)
     , m_selectionEnd(0)
     , m_selectionStartPos(-1)
     , m_selectionEndPos(-1)
     , m_maximalOutlineSize(0)
     , m_pageLogicalHeight(0)
     , m_pageLogicalHeightChanged(false)
     , m_layoutState(0)
     , m_layoutStateDisableCount(0)
+    , m_firstLazyBlock(0)
     , m_renderQuoteHead(0)
     , m_renderCounterCount(0)
 {
     // init RenderObject attributes
     setInline(false);
     
     m_minPreferredLogicalWidth = 0;
     m_maxPreferredLogicalWidth = 0;
 
     setPreferredLogicalWidthsDirty(true, MarkOnlyThis);
@@ skipping 32 matching lines @@
     if (hasColumns())
         return columnInfo()->columnHeight();
     return RenderBlock::availableLogicalHeight(heightType);
 }
 
 bool RenderView::isChildAllowed(RenderObject* child, RenderStyle*) const
 {
     return child->isBox();
 }
 
+void RenderView::markLazyBlocksForLayout()
+{
+    for (RenderLazyBlock* block = m_firstLazyBlock; block; block = block->next())
+        block->setNeedsLayout(true);
+}
+
 void RenderView::layoutContent(const LayoutState& state)
 {
     UNUSED_PARAM(state);
     ASSERT(needsLayout());
 
     RenderBlock::layout();
     if (hasRenderNamedFlowThreads())
         flowThreadController()->layoutRenderNamedFlowThreads();
 #ifndef NDEBUG
     checkLayoutState(state);
@@ skipping 1038 matching lines @@
 #endif
 
     if (layoutState)
         layoutState->m_isPaginated = m_fragmenting;
         
     if (m_flowThreadState != RenderObject::NotInsideFlowThread)
         m_root->setFlowThreadStateIncludingDescendants(m_flowThreadState);
 }
 
 } // namespace WebCore