Properly suspend HTMLDocumentParser

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.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 530 matching lines @@
 
     InspectorCounters::incrementCounter(InspectorCounters::DocumentCounter);
 
     m_lifecycle.advanceTo(DocumentLifecycle::Inactive);
 
     // Since CSSFontSelector requires Document::m_fetcher and StyleEngine owns
     // CSSFontSelector, need to initialize m_styleEngine after initializing
     // m_fetcher.
     m_styleEngine = StyleEngine::create(*this);
 
+    // The parent's parser should be suspended together with all the other objects,
+    // else this new Document would have a new ExecutionContext which suspended state
+    // would not match the one from the parent, and could start loading resources
+    // ignoring the defersLoading flag.
+    ASSERT(!parentDocument() || !parentDocument()->activeDOMObjectsAreSuspended());
+
 #ifndef NDEBUG
     liveDocumentSet().add(this);
 #endif
 }
 
 Document::~Document()
 {
     ASSERT(!renderView());
     ASSERT(!parentTreeScope());
 #if !ENABLE(OILPAN)
@@ skipping 5288 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 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().string().utf8().data());
 }
 #endif