Fix crash in isDocumentDoneLoading()

Source/core/loader/FrameLoader.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  * Copyright (C) 2008 Alp Toker <alp@atoker.com>
  * Copyright (C) Research In Motion Limited 2009. All rights reserved.
  * Copyright (C) 2011 Kris Jordan <krisjordan@gmail.com>
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 894 matching lines @@
 
 FrameLoadType FrameLoader::loadType() const
 {
     return m_loadType;
 }
 
 // This function is an incomprehensible mess and is only used in checkLoadCompleteForThisFrame.
 // If you're thinking of using it elsewhere, stop right now and reconsider your life.
 static bool isDocumentDoneLoading(Document* document)
 {
+    if (!document->loader())
+        return true;
     if (document->loader()->isLoadingMainResource())
         return false;
     if (!document->loadEventFinished()) {
         if (document->loader()->isLoading() || document->isDelayingLoadEvent())
             return false;
     }
     if (document->fetcher()->requestCount())
         return false;
     if (document->processingLoadEvent())
         return false;
@@ skipping 489 matching lines @@
 {
     SandboxFlags flags = m_forcedSandboxFlags;
     if (LocalFrame* parentFrame = m_frame->tree().parent())
         flags |= parentFrame->document()->sandboxFlags();
     if (HTMLFrameOwnerElement* ownerElement = m_frame->ownerElement())
         flags |= ownerElement->sandboxFlags();
     return flags;
 }
 
 } // namespace WebCore