Use attach/detachLayoutTree to signal password counting

third_party/WebKit/Source/core/dom/Document.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2006 Alexey Proskuryakov (ap@webkit.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2011, 2012 Apple Inc. All
  * rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved.
  * (http://www.torchmobile.com/)
  * Copyright (C) 2008, 2009, 2011, 2012 Google Inc. All rights reserved.
@@ skipping 6351 matching lines @@
   if (!m_propertyRegistry && RuntimeEnabledFeatures::cssVariables2Enabled())
     m_propertyRegistry = PropertyRegistry::create();
   return m_propertyRegistry;
 }
 
 void Document::incrementPasswordCount() {
   ++m_passwordCount;
 }
 
 void Document::decrementPasswordCount() {
+  DCHECK_GT(m_passwordCount, 0u);
   --m_passwordCount;
 }
 
 unsigned Document::passwordCount() const {
   return m_passwordCount;
 }
 
 DEFINE_TRACE(Document) {
   visitor->trace(m_importsController);
   visitor->trace(m_docType);
@@ skipping 99 matching lines @@
 }
 
 void showLiveDocumentInstances() {
   WeakDocumentSet& set = liveDocumentSet();
   fprintf(stderr, "There are %u documents currently alive:\n", set.size());
   for (Document* document : set)
     fprintf(stderr, "- Document %p URL: %s\n", document,
             document->url().getString().utf8().data());
 }
 #endif