[svg] Update the <use> shadowtree if a referenced element is removed.

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 948 matching lines @@
 }
 
 void SVGElement::markForLayoutAndParentResourceInvalidation(LayoutObject* renderer)
 {
     ASSERT(renderer);
     LayoutSVGResourceContainer::markForLayoutAndParentResourceInvalidation(renderer, true);
 }
 
 void SVGElement::invalidateInstances()
 {
-    if (!inDocument())
-        return;
-
     if (instanceUpdatesBlocked())
         return;
 
     const WillBeHeapHashSet<RawPtrWillBeWeakMember<SVGElement>>& set = instancesForElement();
     if (set.isEmpty())
         return;
 
     // Mark all use elements referencing 'element' for rebuilding
     for (SVGElement* instance : set) {
         instance->setCorrespondingElement(0);
 
         if (SVGUseElement* element = instance->correspondingUseElement()) {
-            ASSERT(element->inDocument());
-            element->invalidateShadowTree();
+            if (element->inDocument())
+                element->invalidateShadowTree();
         }
     }
 
     svgRareData()->elementInstances().clear();
 
-    document().updateRenderTreeIfNeeded();
+    if (inDocument())
+        document().updateRenderTreeIfNeeded();
 }
 
 SVGElement::InstanceUpdateBlocker::InstanceUpdateBlocker(SVGElement* targetElement)
     : m_targetElement(targetElement)
 {
     if (m_targetElement)
         m_targetElement->setInstanceUpdatesBlocked(true);
 }
 
 SVGElement::InstanceUpdateBlocker::~InstanceUpdateBlocker()
@@ skipping 184 matching lines @@
     Element::trace(visitor);
 }
 
 const AtomicString& SVGElement::eventParameterName()
 {
     DEFINE_STATIC_LOCAL(const AtomicString, evtString, ("evt", AtomicString::ConstructFromLiteral));
     return evtString;
 }
 
 } // namespace blink