Simplify inDetach() assert and make it stronger.

Source/core/dom/Node.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 913 matching lines @@
     ASSERT(document().inStyleRecalc() || isDocumentNode());
     ASSERT(needsAttach());
     ASSERT(!layoutObject() || (layoutObject()->style() && (layoutObject()->parent() || layoutObject()->isLayoutView())));
 
     clearNeedsStyleRecalc();
 
     if (AXObjectCache* cache = document().axObjectCache())
         cache->updateCacheAfterNodeIsAttached(this);
 }
 
-#if ENABLE(ASSERT)
-static Node* detachingNode;
-
-bool Node::inDetach() const
-{
-    return detachingNode == this;
-}
-#endif
-
 void Node::detach(const AttachContext& context)
 {
     ASSERT(document().lifecycle().stateAllowsDetach());
     DocumentLifecycle::DetachScope willDetach(document().lifecycle());
 
-#if ENABLE(ASSERT)
-    // The detaching might trigger destruction of a popup menu window,
-    // with ensuing detachment of its Nodes. In a separate document, so
-    // don't assert for these, but do set detachingNode to the most recent
-    // Node being detached.
-    ASSERT(!detachingNode || detachingNode->document() != document());
-    detachingNode = this;
-#endif
-
     if (layoutObject())
         layoutObject()->destroyAndCleanupAnonymousWrappers();
     setLayoutObject(nullptr);
 
     setStyleChange(NeedsReattachStyleChange);
     clearChildNeedsStyleInvalidation();
-
-#if ENABLE(ASSERT)
-    detachingNode = nullptr;
-#endif
 }
 
 void Node::reattachWhitespaceSiblingsIfNeeded(Text* start)
 {
     for (Node* sibling = start; sibling; sibling = sibling->nextSibling()) {
         if (sibling->isTextNode() && toText(sibling)->containsOnlyWhitespace()) {
             bool hadLayoutObject = !!sibling->layoutObject();
             toText(sibling)->reattachIfNeeded();
             // If sibling's layout object status didn't change we don't need to continue checking
             // other siblings since their layout object status won't change either.
@@ skipping 1504 matching lines @@
 
 void showNodePath(const blink::Node* node)
 {
     if (node)
         node->showNodePathForThis();
     else
         fprintf(stderr, "Cannot showNodePath for (nil)\n");
 }
 
 #endif