Cancel javascript: URL navigations if the frame was navigated.

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.
  * Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) Research In Motion Limited 2010-2011. All rights reserved.
@@ skipping 2164 matching lines @@
     m_lifecycle.advanceTo(DocumentLifecycle::StyleClean);
 }
 
 void Document::detach(const AttachContext& context)
 {
     TRACE_EVENT0("blink", "Document::detach");
     ASSERT(!m_frame || m_frame->tree().childCount() == 0);
     if (!isActive())
         return;
 
+    // Frame navigation can cause a new Document to be attached. Don't allow that, since that will
+    // cause a situation where LocalFrame still has a Document attached after this finishes!
+    // Normally, it shouldn't actually be possible to trigger navigation here. However, plugins
+    // (see below) can cause lots of crazy things to happen, since plugin detach involves nested
+    // message loops.
+    FrameNavigationDisabler navigationDisabler(*m_frame);
+    // Defer widget updates to avoid plugins trying to run script inside ScriptForbiddenScope,
+    // which will crash the renderer after https://crrev.com/200984
     HTMLFrameOwnerElement::UpdateSuspendScope suspendWidgetHierarchyUpdates;
+    // Don't allow script to run in the middle of detach() because a detaching Document is not in a
+    // consistent state.
     ScriptForbiddenScope forbidScript;
     view()->dispose();
     m_markers->prepareForDestruction();
     if (LocalDOMWindow* window = this->domWindow())
         window->willDetachDocumentFromFrame();
 
     m_lifecycle.advanceTo(DocumentLifecycle::Stopping);
 
     if (page())
         page()->documentDetached(this);
@@ skipping 3626 matching lines @@
 #ifndef NDEBUG
 using namespace blink;
 void showLiveDocumentInstances()
 {
     Document::WeakDocumentSet& set = Document::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