*** FOR PROTOTYPE PURPOSES ONLY! NOT INTENDED FOR COMMIT! ***

Source/core/rendering/RenderBlock.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 1287 matching lines @@
         return;
 
     // It's safe to check for control clip here, since controls can never be table cells.
     // If we have a lightweight clip, there can never be any overflow from children.
     if (hasControlClip() && m_overflow)
         clearLayoutOverflow();
 
     invalidateBackgroundObscurationStatus();
 }
 
+void RenderBlock::preLayout()
+{
+    OverflowEventDispatcher dispatcher(this);
+    LayoutRectRecorder recorder(*this);

[eseidel, 2014/02/15 00:37:18]

This won't work, it will expect that layout is done when its destructor is
called.

One of the unfortunate effects of splitting layout() into halves is that all of
our existing RAIIs (like this one) will be confused.  We'll need to instead push
these RAIIs on a stack?

[atreat, 2014/02/18 16:03:57]

Yes, this one I missed and we'll need a stack.  More on that in another comment.

[dsinclair, 2014/02/18 16:07:06]

LayoutRectRecorder should be fine, you just have to make sure you create it in
both the pre and post layout. It's already designed that if you call it multiple
times it will set the oldRepaintRect size and won't over-write it, but it will
over-write newRepaintRect when it's created a second time. So, you shouldn't
need a special stack of them.

+
+    // Update our first letter info now.
+    updateFirstLetter();
+
+    // Table cells call layoutBlock directly, so don't add any logic here.  Put code into
+    // layoutBlock().
+    preLayoutBlock(false, false);
+}
+
+void RenderBlock::postLayout()
+{
+    postLayoutBlock();
+
+    if (frameView()->partialLayout().isStopping())
+        return;
+
+    // It's safe to check for control clip here, since controls can never be table cells.
+    // If we have a lightweight clip, there can never be any overflow from children.
+    if (hasControlClip() && m_overflow)
+        clearLayoutOverflow();
+
+    invalidateBackgroundObscurationStatus();
+}
+
 bool RenderBlock::updateImageLoadingPriorities()
 {
     Vector<ImageResource*> images;
     appendImagesFromStyle(images, *style());
 
     if (images.isEmpty())
         return false;
 
     LayoutRect viewBounds = viewRect();
     LayoutRect objectBounds = absoluteContentBox();
@@ skipping 190 matching lines @@
 
     return oldWidth != logicalWidth() || oldColumnWidth != desiredColumnWidth() || hasBorderOrPaddingLogicalWidthChanged;
 }
 
 void RenderBlock::layoutBlock(bool)
 {
     ASSERT_NOT_REACHED();
     clearNeedsLayout();
 }
 
+void RenderBlock::preLayoutBlock(bool, bool)
+{
+    ASSERT_NOT_REACHED();
+    clearNeedsLayout();
+}
+
+bool RenderBlock::postLayoutBlock()
+{
+    ASSERT_NOT_REACHED();
+    return false;
+}
+
 void RenderBlock::addOverflowFromChildren()
 {
     if (!hasColumns()) {
         if (childrenInline())
             toRenderBlockFlow(this)->addOverflowFromInlineChildren();
         else
             addOverflowFromBlockChildren();
     } else {
         ColumnInfo* colInfo = columnInfo();
         if (columnCount(colInfo)) {
@@ skipping 4116 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace WebCore