[SVG] Resources should be laid out in dependecy order.

Source/core/svg/SVGElement.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2008 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) 2009 Cameron McCormack <cam@mcc.id.au>
  *
  * 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 445 matching lines @@
             break;
 
         SVGElement* element = toSVGElement(node);
 
         // Register us in the parent element map.
         element->updateRelativeLengthsInformation(hasRelativeLengths, this);
         break;
     }
 }
 
+void SVGElement::invalidateRelativeLengthClients(SubtreeLayoutScope* layoutScope)
+{
+    if (!inDocument())
+        return;
+
+    HashSet<SVGElement*>::iterator end = m_elementsWithRelativeLengths.end();
+    for (HashSet<SVGElement*>::iterator it = m_elementsWithRelativeLengths.begin(); it != end; ++it) {

[pdr., 2013/09/23 22:26:02]

This always scares me. Are we sure nothing in this loop can modify
m_elementsWithRelativeLengths? Can we assert it?

[f(malita), 2013/09/23 23:20:33]

Pretty sure:

* the only way to modify m_elementsWithRelativeLengths is via
updateRelativeLengthsInformation, which is only called on node
insertions/removal + svgAttributeChanged().
* the only call in the loop is setNeedsLayout, which should not trigger any of
the above.

I'll see if I can come up with a way to assert this.

+        if (*it == this)
+            continue;
+
+        if ((*it)->renderer() && (*it)->selfHasRelativeLengths())
+            (*it)->renderer()->setNeedsLayout(MarkContainingBlockChain, layoutScope);
+
+        (*it)->invalidateRelativeLengthClients(layoutScope);
+    }
+}
+
 SVGSVGElement* SVGElement::ownerSVGElement() const
 {
     ContainerNode* n = parentOrShadowHostNode();
     while (n) {
         if (n->hasTagName(SVGNames::svgTag))
             return toSVGSVGElement(n);
 
         n = n->parentOrShadowHostNode();
     }
 
@@ skipping 661 matching lines @@
     }
 
     if (name == classAttr)
         return true;
 
     return animatableAttributes.contains(name);
 }
 #endif
 
 }