diff --git a/content/base/public/nsIDocument.h b/content/base/public/nsIDocument.h
index 2605293b22a..fab5aa034a2 100644
--- a/content/base/public/nsIDocument.h
+++ b/content/base/public/nsIDocument.h
@@ -52,13 +52,13 @@
 #include "nsCompatibility.h"
 #include "nsTObserverArray.h"
 #include "nsNodeInfoManager.h"
+#include "nsIStreamListener.h"
+#include "nsIObserver.h"
 
 class nsIContent;
 class nsPresContext;
 class nsIPresShell;
 class nsIDocShell;
-class nsIStreamListener;
-class nsIStreamObserver;
 class nsStyleSet;
 class nsIStyleSheet;
 class nsIStyleRule;
@@ -77,7 +77,6 @@ class nsIChannel;
 class nsIPrincipal;
 class nsIDOMDocument;
 class nsIDOMDocumentType;
-class nsIObserver;
 class nsScriptLoader;
 class nsIContentSink;
 class nsIScriptEventManager;
@@ -97,8 +96,8 @@ class nsFrameLoader;
 
 // IID for the nsIDocument interface
 #define NS_IDOCUMENT_IID      \
-  { 0xd5b1e3c5, 0x85dc, 0x403e, \
-    { 0xbb, 0x4a, 0x54, 0x66, 0xdc, 0xbe, 0x15, 0x69 } }
+{ 0x189ebc9e, 0x779b, 0x4c49, \
+ { 0x90, 0x8b, 0x9a, 0x80, 0x25, 0x9b, 0xaf, 0xa7 } }
 
 // Flag for AddStyleSheet().
 #define NS_STYLESHEET_FROM_CATALOG                (1 << 0)
@@ -1004,6 +1003,98 @@ public:
   virtual void TryCancelFrameLoaderInitialization(nsIDocShell* aShell) = 0;
   //  Returns true if the frame loader of aShell is in the finalization list.
   virtual PRBool FrameLoaderScheduledToBeFinalized(nsIDocShell* aShell) = 0;
+
+  /**
+   * Check whether this document is a root document that is not an
+   * external resource.
+   */
+  PRBool IsRootDisplayDocument() const
+  {
+    return !mParentDocument && !mDisplayDocument;
+  }
+
+  /**
+   * Get the document for which this document is an external resource.  This
+   * will be null if this document is not an external resource.  Otherwise,
+   * GetDisplayDocument() will return a non-null document, and
+   * GetDisplayDocument()->GetDisplayDocument() is guaranteed to be null.
+   */
+  nsIDocument* GetDisplayDocument() const
+  {
+    return mDisplayDocument;
+  }
+  
+  /**
+   * Set the display document for this document.  aDisplayDocument must not be
+   * null.
+   */
+  void SetDisplayDocument(nsIDocument* aDisplayDocument)
+  {
+    NS_PRECONDITION(!GetPrimaryShell() &&
+                    !nsCOMPtr<nsISupports>(GetContainer()) &&
+                    !GetWindow() &&
+                    !GetScriptGlobalObject(),
+                    "Shouldn't set mDisplayDocument on documents that already "
+                    "have a presentation or a docshell or a window");
+    NS_PRECONDITION(aDisplayDocument != this, "Should be different document");
+    NS_PRECONDITION(!aDisplayDocument->GetDisplayDocument(),
+                    "Display documents should not nest");
+    mDisplayDocument = aDisplayDocument;
+  }
+
+  /**
+   * A class that represents an external resource load that has begun but
+   * doesn't have a document yet.  Observers can be registered on this object,
+   * and will be notified after the document is created.  Observers registered
+   * after the document has been created will NOT be notified.  When observers
+   * are notified, the subject will be the newly-created document, the topic
+   * will be "external-resource-document-created", and the data will be null.
+   * If document creation fails for some reason, observers will still be
+   * notified, with a null document pointer.
+   */
+  class ExternalResourceLoad : public nsISupports
+  {
+  public:
+    virtual ~ExternalResourceLoad() {}
+
+    void AddObserver(nsIObserver* aObserver) {
+      NS_PRECONDITION(aObserver, "Must have observer");
+      mObservers.AppendElement(aObserver);
+    }
+
+    const nsTArray< nsCOMPtr<nsIObserver> > & Observers() {
+      return mObservers;
+    }
+  protected:
+    nsAutoTArray< nsCOMPtr<nsIObserver>, 8 > mObservers;    
+  };
+
+  /**
+   * Request an external resource document for aURI.  This will return the
+   * resource document if available.  If one is not available yet, it will
+   * start loading as needed, and the pending load object will be returned in
+   * aPendingLoad so that the caller can register an observer to wait for the
+   * load.  If this function returns null and doesn't return a pending load,
+   * that means that there is no resource document for this URI and won't be
+   * one in the future.
+   *
+   * @param aURI the URI to get
+   * @param aRequestingNode the node making the request
+   * @param aPendingLoad the pending load for this request, if any
+   */
+  virtual nsIDocument*
+    RequestExternalResource(nsIURI* aURI,
+                            nsINode* aRequestingNode,
+                            ExternalResourceLoad** aPendingLoad) = 0;
+
+  /**
+   * Enumerate the external resource documents associated with this document.
+   * The enumerator callback should return PR_TRUE to continue enumerating, or
+   * PR_FALSE to stop.
+   */
+  virtual void EnumerateExternalResources(nsSubDocEnumFunc aCallback,
+                                          void* aData) = 0;
+  
 protected:
   ~nsIDocument()
   {
@@ -1100,6 +1191,11 @@ protected:
   nsCOMArray<nsINode> mSubtreeModifiedTargets;
   PRUint32            mSubtreeModifiedDepth;
 
+  // If we're an external resource document, this will be non-null and will
+  // point to our "display document": the one that all resource lookups should
+  // go to.
+  nsCOMPtr<nsIDocument> mDisplayDocument;
+
 private:
   // JSObject cache. Only to be used for performance
   // optimizations. This will be set once this document is touched
diff --git a/content/base/src/nsContentUtils.cpp b/content/base/src/nsContentUtils.cpp
index 4941911c9fd..9980d97e4d5 100644
--- a/content/base/src/nsContentUtils.cpp
+++ b/content/base/src/nsContentUtils.cpp
@@ -2911,6 +2911,10 @@ nsContentUtils::IsInChromeDocshell(nsIDocument *aDocument)
     return PR_FALSE;
   }
 
+  if (aDocument->GetDisplayDocument()) {
+    return IsInChromeDocshell(aDocument->GetDisplayDocument());
+  }
+
   nsCOMPtr<nsISupports> docContainer = aDocument->GetContainer();
   nsCOMPtr<nsIDocShellTreeItem> docShell(do_QueryInterface(docContainer));
   PRInt32 itemType = nsIDocShellTreeItem::typeContent;
diff --git a/content/base/src/nsDataDocumentContentPolicy.cpp b/content/base/src/nsDataDocumentContentPolicy.cpp
index 4bc8ad4d6d9..4f198cfe6a6 100644
--- a/content/base/src/nsDataDocumentContentPolicy.cpp
+++ b/content/base/src/nsDataDocumentContentPolicy.cpp
@@ -72,7 +72,28 @@ nsDataDocumentContentPolicy::ShouldLoad(PRUint32 aContentType,
       doc = do_QueryInterface(domDoc);
     }
   }
-  if (aContentType != nsIContentPolicy::TYPE_DTD && doc && doc->IsLoadedAsData()) {
+
+  // DTDs are always OK to load
+  if (!doc || aContentType == nsIContentPolicy::TYPE_DTD) {
+    return NS_OK;
+  }
+
+  // Nothing else is OK to load for data documents
+  if (doc->IsLoadedAsData()) {
+    *aDecision = nsIContentPolicy::REJECT_TYPE;
+    return NS_OK;
+  }
+
+  // Allow all loads for non-external-resource documents
+  if (!doc->GetDisplayDocument()) {
+    return NS_OK;
+  }
+
+  // For external resources, blacklist some load types
+  if (aContentType == nsIContentPolicy::TYPE_OBJECT ||
+      aContentType == nsIContentPolicy::TYPE_DOCUMENT ||
+      aContentType == nsIContentPolicy::TYPE_SUBDOCUMENT ||
+      aContentType == nsIContentPolicy::TYPE_SCRIPT) {
     *aDecision = nsIContentPolicy::REJECT_TYPE;
   }
 
diff --git a/content/base/src/nsDocument.cpp b/content/base/src/nsDocument.cpp
index 8c15fbab17b..7dab88d4bd0 100644
--- a/content/base/src/nsDocument.cpp
+++ b/content/base/src/nsDocument.cpp
@@ -157,11 +157,23 @@ static NS_DEFINE_CID(kDOMEventGroupCID, NS_DOMEVENTGROUP_CID);
 #include "nsCycleCollector.h"
 #include "nsCCUncollectableMarker.h"
 #include "nsIContentPolicy.h"
+#include "nsContentPolicyUtils.h"
+#include "nsICategoryManager.h"
+#include "nsIDocumentLoaderFactory.h"
+#include "nsIContentViewer.h"
+#include "nsIXMLContentSink.h"
+#include "nsIChannelEventSink.h"
+#include "nsContentErrors.h"
+#include "nsIXULDocument.h"
+#include "nsIProgressEventSink.h"
+#include "nsISecurityEventSink.h"
+#include "nsIPrompt.h"
 
 #include "nsFrameLoader.h"
 
 #include "mozAutoDocUpdate.h"
 
+
 #ifdef MOZ_LOGGING
 // so we can get logging even in release builds
 #define FORCE_PR_LOG 1
@@ -718,6 +730,433 @@ nsOnloadBlocker::SetLoadFlags(nsLoadFlags aLoadFlags)
   return NS_OK;
 }
 
+// ==================================================================
+
+nsExternalResourceMap::nsExternalResourceMap()
+  : mHaveShutDown(PR_FALSE)
+{
+  mMap.Init();
+  mPendingLoads.Init();
+}
+
+nsIDocument*
+nsExternalResourceMap::RequestResource(nsIURI* aURI,
+                                       nsINode* aRequestingNode,
+                                       nsDocument* aDisplayDocument,
+                                       ExternalResourceLoad** aPendingLoad)
+{
+  // If we ever start allowing non-same-origin loads here, we might need to do
+  // something interesting with aRequestingPrincipal even for the hashtable
+  // gets.
+  NS_PRECONDITION(aURI, "Must have a URI");
+  NS_PRECONDITION(aRequestingNode, "Must have a node");
+  *aPendingLoad = nsnull;
+  if (mHaveShutDown) {
+    return nsnull;
+  }
+  
+  // First, make sure we strip the ref from aURI.
+  nsCOMPtr<nsIURI> clone;
+  aURI->Clone(getter_AddRefs(clone));
+  if (!clone) {
+    return nsnull;
+  }
+  nsCOMPtr<nsIURL> url(do_QueryInterface(clone));
+  if (url) {
+    url->SetRef(EmptyCString());
+  }
+  
+  ExternalResource* resource;
+  mMap.Get(clone, &resource);
+  if (resource) {
+    return resource->mDocument;
+  }
+
+  nsRefPtr<PendingLoad> load;
+  mPendingLoads.Get(clone, getter_AddRefs(load));
+  if (load) {
+    NS_ADDREF(*aPendingLoad = load);
+    return nsnull;
+  }
+
+  load = new PendingLoad(aDisplayDocument);
+  if (!load) {
+    return nsnull;
+  }
+
+  if (!mPendingLoads.Put(clone, load)) {
+    return nsnull;
+  }
+
+  if (NS_FAILED(load->StartLoad(clone, aRequestingNode))) {
+    // Make sure we don't thrash things by trying this load again, since
+    // chances are it failed for good reasons (security check, etc).
+    AddExternalResource(clone, nsnull, nsnull, aDisplayDocument);
+  } else {
+    NS_ADDREF(*aPendingLoad = load);
+  }
+
+  return nsnull;
+}
+
+struct
+nsExternalResourceEnumArgs
+{
+  nsIDocument::nsSubDocEnumFunc callback;
+  void *data;
+};
+
+PR_STATIC_CALLBACK(PLDHashOperator)
+ExternalResourceEnumerator(nsIURI* aKey,
+                           nsExternalResourceMap::ExternalResource* aData,
+                           void* aClosure)
+{
+  nsExternalResourceEnumArgs* args =
+    static_cast<nsExternalResourceEnumArgs*>(aClosure);
+  PRBool next = args->callback(aData->mDocument, args->data);
+  return next ? PL_DHASH_NEXT : PL_DHASH_STOP;
+}
+
+void
+nsExternalResourceMap::EnumerateResources(nsIDocument::nsSubDocEnumFunc aCallback,
+                                          void* aData)
+{
+  nsExternalResourceEnumArgs args = { aCallback, aData };
+  mMap.EnumerateRead(ExternalResourceEnumerator, &args);
+}
+
+PR_STATIC_CALLBACK(PLDHashOperator)
+ExternalResourceTraverser(nsIURI* aKey,
+                          nsExternalResourceMap::ExternalResource* aData,
+                          void* aClosure)
+{
+  nsCycleCollectionTraversalCallback *cb = 
+    static_cast<nsCycleCollectionTraversalCallback*>(aClosure);
+
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb,
+                                     "mExternalResourceMap.mMap entry"
+                                     "->mDocument");
+  cb->NoteXPCOMChild(aData->mDocument);
+
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb,
+                                     "mExternalResourceMap.mMap entry"
+                                     "->mViewer");
+  cb->NoteXPCOMChild(aData->mViewer);
+
+  NS_CYCLE_COLLECTION_NOTE_EDGE_NAME(*cb,
+                                     "mExternalResourceMap.mMap entry"
+                                     "->mLoadGroup");
+  cb->NoteXPCOMChild(aData->mLoadGroup);
+
+  return PL_DHASH_NEXT;
+}
+
+void
+nsExternalResourceMap::Traverse(nsCycleCollectionTraversalCallback* aCallback) const
+{
+  // mPendingLoads will get cleared out as the requests complete, so
+  // no need to worry about those here.
+  mMap.EnumerateRead(ExternalResourceTraverser, aCallback);
+}
+
+nsresult
+nsExternalResourceMap::AddExternalResource(nsIURI* aURI,
+                                           nsIDocumentViewer* aViewer,
+                                           nsILoadGroup* aLoadGroup,
+                                           nsIDocument* aDisplayDocument)
+{
+  NS_PRECONDITION(aURI, "Unexpected call");
+  NS_PRECONDITION((aViewer && aLoadGroup) || (!aViewer && !aLoadGroup),
+                  "Must have both or neither");
+  
+  nsRefPtr<PendingLoad> load;
+  mPendingLoads.Get(aURI, getter_AddRefs(load));
+  mPendingLoads.Remove(aURI);
+
+  nsresult rv = NS_OK;
+  
+  nsCOMPtr<nsIDocument> doc;
+  if (aViewer) {
+    aViewer->GetDocument(getter_AddRefs(doc));
+    NS_ASSERTION(doc, "Must have a document");
+
+    nsCOMPtr<nsIXULDocument> xulDoc = do_QueryInterface(doc);
+    if (xulDoc) {
+      // We don't handle XUL stuff here yet.
+      rv = NS_ERROR_NOT_AVAILABLE;
+    } else {
+      doc->SetDisplayDocument(aDisplayDocument);
+
+      rv = aViewer->Init(nsnull, nsRect(0, 0, 0, 0));
+      if (NS_SUCCEEDED(rv)) {
+        rv = aViewer->Open(nsnull, nsnull);
+      }
+    }
+    
+    if (NS_FAILED(rv)) {
+      doc = nsnull;
+      aViewer = nsnull;
+      aLoadGroup = nsnull;
+    }
+  }
+
+  ExternalResource* newResource = new ExternalResource();
+  if (newResource && !mMap.Put(aURI, newResource)) {
+    delete newResource;
+    newResource = nsnull;
+    if (NS_SUCCEEDED(rv)) {
+      rv = NS_ERROR_OUT_OF_MEMORY;
+    }
+  }
+
+  if (newResource) {
+    newResource->mDocument = doc;
+    newResource->mViewer = aViewer;
+    newResource->mLoadGroup = aLoadGroup;
+  }
+
+  const nsTArray< nsCOMPtr<nsIObserver> > & obs = load->Observers();
+  for (PRUint32 i = 0; i < obs.Length(); ++i) {
+    obs[i]->Observe(doc, "external-resource-document-created", nsnull);
+  }
+
+  return rv;
+}
+
+NS_IMPL_ISUPPORTS2(nsExternalResourceMap::PendingLoad,
+                   nsIStreamListener,
+                   nsIRequestObserver)
+
+NS_IMETHODIMP
+nsExternalResourceMap::PendingLoad::OnStartRequest(nsIRequest *aRequest,
+                                                   nsISupports *aContext)
+{
+  nsExternalResourceMap& map = mDisplayDocument->ExternalResourceMap();
+  if (map.HaveShutDown()) {
+    return NS_BINDING_ABORTED;
+  }
+
+  nsCOMPtr<nsIDocumentViewer> viewer;
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  nsresult rv = SetupViewer(aRequest, getter_AddRefs(viewer),
+                            getter_AddRefs(loadGroup));
+
+  // Make sure to do this no matter what
+  nsresult rv2 = map.AddExternalResource(mURI, viewer, loadGroup,
+                                         mDisplayDocument);
+  if (NS_FAILED(rv)) {
+    return rv;
+  }
+  if (NS_FAILED(rv2)) {
+    mTargetListener = nsnull;
+    return rv2;
+  }
+  
+  return mTargetListener->OnStartRequest(aRequest, aContext);
+}
+
+nsresult
+nsExternalResourceMap::PendingLoad::SetupViewer(nsIRequest* aRequest,
+                                                nsIDocumentViewer** aViewer,
+                                                nsILoadGroup** aLoadGroup)
+{
+  NS_PRECONDITION(!mTargetListener, "Unexpected call to OnStartRequest");
+  *aViewer = nsnull;
+  *aLoadGroup = nsnull;
+  
+  nsCOMPtr<nsIChannel> chan(do_QueryInterface(aRequest));
+  NS_ENSURE_TRUE(chan, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<nsIHttpChannel> httpChannel(do_QueryInterface(aRequest));
+  if (httpChannel) {
+    PRBool requestSucceeded;
+    if (NS_FAILED(httpChannel->GetRequestSucceeded(&requestSucceeded)) ||
+        !requestSucceeded) {
+      // Bail out on this load, since it looks like we have an HTTP error page
+      return NS_BINDING_ABORTED;
+    }
+  }
+ 
+  nsCAutoString type;
+  chan->GetContentType(type);
+
+  nsCOMPtr<nsILoadGroup> loadGroup;
+  chan->GetLoadGroup(getter_AddRefs(loadGroup));
+
+  // Give this document its own loadgroup
+  nsCOMPtr<nsILoadGroup> newLoadGroup =
+        do_CreateInstance(NS_LOADGROUP_CONTRACTID);
+  NS_ENSURE_TRUE(newLoadGroup, NS_ERROR_OUT_OF_MEMORY);
+  newLoadGroup->SetLoadGroup(loadGroup);
+
+  nsCOMPtr<nsIInterfaceRequestor> callbacks;
+  loadGroup->GetNotificationCallbacks(getter_AddRefs(callbacks));
+
+  nsCOMPtr<nsIInterfaceRequestor> newCallbacks =
+    new LoadgroupCallbacks(callbacks);
+  newLoadGroup->SetNotificationCallbacks(newCallbacks);
+
+  // This is some serious hackery cribbed from docshell
+  nsCOMPtr<nsICategoryManager> catMan =
+    do_GetService(NS_CATEGORYMANAGER_CONTRACTID);
+  NS_ENSURE_TRUE(catMan, NS_ERROR_NOT_AVAILABLE);
+  nsXPIDLCString contractId;
+  nsresult rv = catMan->GetCategoryEntry("Gecko-Content-Viewers", type.get(),
+                                         getter_Copies(contractId));
+  NS_ENSURE_SUCCESS(rv, rv);
+  nsCOMPtr<nsIDocumentLoaderFactory> docLoaderFactory =
+    do_GetService(contractId);
+  NS_ENSURE_TRUE(docLoaderFactory, NS_ERROR_NOT_AVAILABLE);
+
+  nsCOMPtr<nsIContentViewer> viewer;
+  nsCOMPtr<nsIStreamListener> listener;
+  rv = docLoaderFactory->CreateInstance("external-resource", chan, newLoadGroup,
+                                        type.get(), nsnull, nsnull,
+                                        getter_AddRefs(listener),
+                                        getter_AddRefs(viewer));
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  nsCOMPtr<nsIDocumentViewer> docViewer = do_QueryInterface(viewer);
+  NS_ENSURE_TRUE(docViewer, NS_ERROR_UNEXPECTED);
+
+  nsCOMPtr<nsIParser> parser = do_QueryInterface(listener);
+  if (!parser) {
+    /// We don't want to deal with the various fake documents yet
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  // We can't handle HTML and other weird things here yet.
+  nsIContentSink* sink = parser->GetContentSink();
+  nsCOMPtr<nsIXMLContentSink> xmlSink = do_QueryInterface(sink);
+  if (!xmlSink) {
+    return NS_ERROR_NOT_IMPLEMENTED;
+  }
+
+  listener.swap(mTargetListener);
+  docViewer.swap(*aViewer);
+  newLoadGroup.swap(*aLoadGroup);
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+nsExternalResourceMap::PendingLoad::OnDataAvailable(nsIRequest* aRequest,
+                                                    nsISupports* aContext,
+                                                    nsIInputStream* aStream,
+                                                    PRUint32 aOffset,
+                                                    PRUint32 aCount)
+{
+  NS_PRECONDITION(mTargetListener, "Shouldn't be getting called!");
+  if (mDisplayDocument->ExternalResourceMap().HaveShutDown()) {
+    return NS_BINDING_ABORTED;
+  }
+  return mTargetListener->OnDataAvailable(aRequest, aContext, aStream, aOffset,
+                                          aCount);
+}
+
+NS_IMETHODIMP
+nsExternalResourceMap::PendingLoad::OnStopRequest(nsIRequest* aRequest,
+                                                  nsISupports* aContext,
+                                                  nsresult aStatus)
+{
+  // mTargetListener might be null if SetupViewer or AddExternalResource failed
+  if (mTargetListener) {
+    nsCOMPtr<nsIStreamListener> listener;
+    mTargetListener.swap(listener);
+    return listener->OnStopRequest(aRequest, aContext, aStatus);
+  }
+
+  return NS_OK;
+}
+
+nsresult
+nsExternalResourceMap::PendingLoad::StartLoad(nsIURI* aURI,
+                                              nsINode* aRequestingNode)
+{
+  NS_PRECONDITION(aURI, "Must have a URI");
+  NS_PRECONDITION(aRequestingNode, "Must have a node");
+
+  // Time to start a load.  First, the security checks.
+
+  nsIPrincipal* requestingPrincipal = aRequestingNode->NodePrincipal();
+
+  nsresult rv = nsContentUtils::GetSecurityManager()->
+    CheckLoadURIWithPrincipal(requestingPrincipal, aURI,
+                              nsIScriptSecurityManager::STANDARD);
+  NS_ENSURE_SUCCESS(rv, rv);
+  
+  rv = requestingPrincipal->CheckMayLoad(aURI, PR_TRUE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  PRInt16 shouldLoad = nsIContentPolicy::ACCEPT;
+  rv = NS_CheckContentLoadPolicy(nsIContentPolicy::TYPE_OTHER,
+                                 aURI,
+                                 requestingPrincipal,
+                                 aRequestingNode,
+                                 EmptyCString(), //mime guess
+                                 nsnull,         //extra
+                                 &shouldLoad,
+                                 nsContentUtils::GetContentPolicy(),
+                                 nsContentUtils::GetSecurityManager());
+  if (NS_FAILED(rv)) return rv;
+  if (NS_CP_REJECTED(shouldLoad)) {
+    // Disallowed by content policy
+    return NS_ERROR_CONTENT_BLOCKED;
+  }
+
+  nsIDocument* doc = aRequestingNode->GetOwnerDoc();
+  if (!doc) {
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
+  nsCOMPtr<nsILoadGroup> loadGroup = doc->GetDocumentLoadGroup();
+  nsCOMPtr<nsIChannel> channel;
+  rv = NS_NewChannel(getter_AddRefs(channel), aURI, nsnull, loadGroup);
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  mURI = aURI;
+
+  nsCOMPtr<nsIInterfaceRequestor> req = nsContentUtils::GetSameOriginChecker();
+  NS_ENSURE_TRUE(req, NS_ERROR_OUT_OF_MEMORY);
+
+  channel->SetNotificationCallbacks(req);
+  return channel->AsyncOpen(this, nsnull);
+}
+
+NS_IMPL_ISUPPORTS1(nsExternalResourceMap::LoadgroupCallbacks,
+                   nsIInterfaceRequestor)
+
+NS_IMETHODIMP
+nsExternalResourceMap::LoadgroupCallbacks::GetInterface(const nsIID & aIID,
+                                                        void **aSink)
+{
+#define IID_IS(_i) aIID.Equals(NS_GET_IID(_i))
+  if (mCallbacks &&
+      (IID_IS(nsIProgressEventSink) ||
+       IID_IS(nsIChannelEventSink) ||
+       IID_IS(nsISecurityEventSink) ||
+       IID_IS(nsIPrompt) ||
+       IID_IS(nsIAuthPrompt) ||
+       IID_IS(nsIAuthPrompt2) ||
+       IID_IS(nsIApplicationCacheContainer) ||
+       // XXXbz evil hack for cookies for now
+       IID_IS(nsIDOMWindow) ||
+       IID_IS(nsIDocShellTreeItem))) {
+    return mCallbacks->GetInterface(aIID, aSink);
+  }
+#undef IID_IS
+
+  *aSink = nsnull;
+  return NS_NOINTERFACE;
+}
+
+nsExternalResourceMap::ExternalResource::~ExternalResource()
+{
+  if (mViewer) {
+    mViewer->Close(nsnull);
+    mViewer->Destroy();
+  }
+}
+
 // ==================================================================
 // =
 // ==================================================================
@@ -1194,7 +1633,8 @@ SubDocTraverser(PLDHashTable *table, PLDHashEntryHdr *hdr, PRUint32 number,
 }
 
 PR_STATIC_CALLBACK(PLDHashOperator)
-RadioGroupsTraverser(const nsAString& aKey, nsAutoPtr<nsRadioGroupStruct>& aData, void* aClosure)
+RadioGroupsTraverser(const nsAString& aKey, nsRadioGroupStruct* aData,
+                     void* aClosure)
 {
   nsCycleCollectionTraversalCallback *cb = 
     static_cast<nsCycleCollectionTraversalCallback*>(aClosure);
@@ -1261,6 +1701,8 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDocument)
 
   tmp->mIdentifierMap.EnumerateEntries(IdentifierMapEntryTraverse, &cb);
 
+  tmp->mExternalResourceMap.Traverse(&cb);
+
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mNodeInfo)
 
   // Traverse the mChildren nsAttrAndChildArray.
@@ -1276,6 +1718,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDocument)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NATIVE_MEMBER(mNodeInfoManager,
                                                   nsNodeInfoManager)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mSecurityInfo)
+  NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mDisplayDocument)
 
   // Traverse all nsDocument nsCOMPtrs.
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mParser)
@@ -1284,7 +1727,7 @@ NS_IMPL_CYCLE_COLLECTION_TRAVERSE_BEGIN(nsDocument)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mDOMStyleSheets)
   NS_IMPL_CYCLE_COLLECTION_TRAVERSE_NSCOMPTR(mScriptLoader)
 
-  tmp->mRadioGroups.Enumerate(RadioGroupsTraverser, &cb);
+  tmp->mRadioGroups.EnumerateRead(RadioGroupsTraverser, &cb);
 
   // The boxobject for an element will only exist as long as it's in the
   // document, so we'll traverse the table here instead of from the element.
@@ -1326,6 +1769,9 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDocument)
   // from the doc.
   tmp->DestroyLinkMap();
 
+  // Clear out our external resources
+  tmp->mExternalResourceMap.Shutdown();
+
   nsAutoScriptBlocker scriptBlocker;
 
   // Unlink the mChildren nsAttrAndChildArray.
@@ -1336,6 +1782,7 @@ NS_IMPL_CYCLE_COLLECTION_UNLINK_BEGIN(nsDocument)
   }
 
   NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mCachedRootContent)
+  NS_IMPL_CYCLE_COLLECTION_UNLINK_NSCOMPTR(mDisplayDocument)
 
   NS_IMPL_CYCLE_COLLECTION_UNLINK_USERDATA
 
@@ -1711,6 +2158,9 @@ nsDocument::StartDocumentLoad(const char* aCommand, nsIChannel* aChannel,
 
     // styles
     CSSLoader()->SetEnabled(PR_FALSE); // Do not load/process styles when loading as data
+  } else if (nsCRT::strcmp("external-resource", aCommand) == 0) {
+    // Allow CSS, but not scripts
+    ScriptLoader()->SetEnabled(PR_FALSE);
   }
 
   mMayStartLayout = PR_FALSE;
@@ -4703,6 +5153,29 @@ nsDocument::FrameLoaderScheduledToBeFinalized(nsIDocShell* aShell)
   return PR_FALSE;
 }
 
+nsIDocument*
+nsDocument::RequestExternalResource(nsIURI* aURI,
+                                    nsINode* aRequestingNode,
+                                    ExternalResourceLoad** aPendingLoad)
+{
+  NS_PRECONDITION(aURI, "Must have a URI");
+  NS_PRECONDITION(aRequestingNode, "Must have a node");
+  if (mDisplayDocument) {
+    return mDisplayDocument->RequestExternalResource(aURI,
+                                                     aRequestingNode,
+                                                     aPendingLoad);
+  }
+
+  return mExternalResourceMap.RequestResource(aURI, aRequestingNode,
+                                              this, aPendingLoad);
+}
+
+void
+nsDocument::EnumerateExternalResources(nsSubDocEnumFunc aCallback, void* aData)
+{
+  mExternalResourceMap.EnumerateResources(aCallback, aData);
+}
+
 struct DirTable {
   const char* mName;
   PRUint8     mValue;
@@ -5860,20 +6333,20 @@ PRBool
 nsDocument::IsScriptEnabled()
 {
   nsCOMPtr<nsIScriptSecurityManager> sm(do_GetService(NS_SCRIPTSECURITYMANAGER_CONTRACTID));
-  NS_ENSURE_TRUE(sm, PR_TRUE);
+  NS_ENSURE_TRUE(sm, PR_FALSE);
 
   nsIScriptGlobalObject* globalObject = GetScriptGlobalObject();
-  NS_ENSURE_TRUE(globalObject, PR_TRUE);
+  NS_ENSURE_TRUE(globalObject, PR_FALSE);
 
   nsIScriptContext *scriptContext = globalObject->GetContext();
-  NS_ENSURE_TRUE(scriptContext, PR_TRUE);
+  NS_ENSURE_TRUE(scriptContext, PR_FALSE);
 
   JSContext* cx = (JSContext *) scriptContext->GetNativeContext();
-  NS_ENSURE_TRUE(cx, PR_TRUE);
+  NS_ENSURE_TRUE(cx, PR_FALSE);
 
   PRBool enabled;
   nsresult rv = sm->CanExecuteScripts(cx, NodePrincipal(), &enabled);
-  NS_ENSURE_SUCCESS(rv, PR_TRUE);
+  NS_ENSURE_SUCCESS(rv, PR_FALSE);
   return enabled;
 }
 
@@ -6396,6 +6869,11 @@ nsDocument::Destroy()
 
   nsContentList::OnDocumentDestroy(this);
 
+  // Shut down our external resource map.  We might not need this for
+  // leak-fixing if we fix DocumentViewerImpl to do cycle-collection, but
+  // tearing down all those frame trees right now is the right thing to do.
+  mExternalResourceMap.Shutdown();
+
   // XXX We really should let cycle collection do this, but that currently still
   //     leaks (see https://bugzilla.mozilla.org/show_bug.cgi?id=406684).
   //     When we start relying on cycle collection again we should remove the
@@ -6437,6 +6915,11 @@ nsDocument::GetLayoutHistoryState() const
 void
 nsDocument::BlockOnload()
 {
+  if (mDisplayDocument) {
+    mDisplayDocument->BlockOnload();
+    return;
+  }
+  
   // If mScriptGlobalObject is null, we shouldn't be messing with the loadgroup
   // -- it's not ours.
   if (mOnloadBlockCount == 0 && mScriptGlobalObject) {
@@ -6451,6 +6934,11 @@ nsDocument::BlockOnload()
 void
 nsDocument::UnblockOnload(PRBool aFireSync)
 {
+  if (mDisplayDocument) {
+    mDisplayDocument->UnblockOnload(aFireSync);
+    return;
+  }
+
   if (mOnloadBlockCount == 0) {
     NS_NOTREACHED("More UnblockOnload() calls than BlockOnload() calls; dropping call");
     return;
@@ -6498,12 +6986,14 @@ nsDocument::PostUnblockOnloadEvent()
 void
 nsDocument::DoUnblockOnload()
 {
-  NS_ASSERTION(mOnloadBlockCount != 0,
-               "Shouldn't have a count of zero here, since we stabilized in "
-               "PostUnblockOnloadEvent");
+  NS_PRECONDITION(!mDisplayDocument,
+                  "Shouldn't get here for resource document");
+  NS_PRECONDITION(mOnloadBlockCount != 0,
+                  "Shouldn't have a count of zero here, since we stabilized in "
+                  "PostUnblockOnloadEvent");
   
   --mOnloadBlockCount;
-  
+
   if (mOnloadBlockCount != 0) {
     // We blocked again after the last unblock.  Nothing to do here.  We'll
     // post a new event when we unblock again.
diff --git a/content/base/src/nsDocument.h b/content/base/src/nsDocument.h
index 7346d682265..640b3ad73f3 100644
--- a/content/base/src/nsDocument.h
+++ b/content/base/src/nsDocument.h
@@ -108,6 +108,8 @@
 #include "nsPresShellIterator.h"
 #include "nsContentUtils.h"
 #include "nsThreadUtils.h"
+#include "nsIDocumentViewer.h"
+#include "nsIInterfaceRequestor.h"
 
 #define XML_DECLARATION_BITS_DECLARATION_EXISTS   (1 << 0)
 #define XML_DECLARATION_BITS_ENCODING_EXISTS      (1 << 1)
@@ -383,6 +385,117 @@ private:
   ~nsOnloadBlocker() {}
 };
 
+class nsExternalResourceMap
+{
+public:
+  typedef nsIDocument::ExternalResourceLoad ExternalResourceLoad;
+  nsExternalResourceMap();
+
+  /**
+   * Request an external resource document.  This does exactly what
+   * nsIDocument::RequestExternalResource is documented to do.
+   */
+  nsIDocument* RequestResource(nsIURI* aURI,
+                               nsINode* aRequestingNode,
+                               nsDocument* aDisplayDocument,
+                               ExternalResourceLoad** aPendingLoad);
+
+  /**
+   * Enumerate the resource documents.  See
+   * nsIDocument::EnumerateExternalResources.
+   */
+  void EnumerateResources(nsIDocument::nsSubDocEnumFunc aCallback, void* aData);
+
+  /**
+   * Traverse ourselves for cycle-collection
+   */
+  void Traverse(nsCycleCollectionTraversalCallback* aCallback) const;
+
+  /**
+   * Shut ourselves down (used for cycle-collection unlink), as well
+   * as for document destruction.
+   */
+  void Shutdown()
+  {
+    mPendingLoads.Clear();
+    mMap.Clear();
+    mHaveShutDown = PR_TRUE;
+  }
+
+  PRBool HaveShutDown() const
+  {
+    return mHaveShutDown;
+  }
+
+  // Needs to be public so we can traverse them sanely
+  struct ExternalResource
+  {
+    ~ExternalResource();
+    nsCOMPtr<nsIDocument> mDocument;
+    nsCOMPtr<nsIContentViewer> mViewer;
+    nsCOMPtr<nsILoadGroup> mLoadGroup;
+  };
+
+protected:
+  class PendingLoad : public ExternalResourceLoad,
+                      public nsIStreamListener
+  {
+  public:
+    PendingLoad(nsDocument* aDisplayDocument) :
+      mDisplayDocument(aDisplayDocument)
+    {}
+
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSISTREAMLISTENER
+    NS_DECL_NSIREQUESTOBSERVER
+
+    /**
+     * Start aURI loading.  This will perform the necessary security checks and
+     * so forth.
+     */
+    nsresult StartLoad(nsIURI* aURI, nsINode* aRequestingNode);
+
+    /**
+     * Set up an nsIDocumentViewer based on aRequest.  This is guaranteed to
+     * put null in *aViewer and *aLoadGroup on all failures.
+     */
+    nsresult SetupViewer(nsIRequest* aRequest, nsIDocumentViewer** aViewer,
+                         nsILoadGroup** aLoadGroup);
+
+  private:
+    nsRefPtr<nsDocument> mDisplayDocument;
+    nsCOMPtr<nsIStreamListener> mTargetListener;
+    nsCOMPtr<nsIURI> mURI;
+  };
+  friend class PendingLoad;
+
+  class LoadgroupCallbacks : public nsIInterfaceRequestor
+  {
+  public:
+    LoadgroupCallbacks(nsIInterfaceRequestor* aOtherCallbacks)
+      : mCallbacks(aOtherCallbacks)
+    {}
+    NS_DECL_ISUPPORTS
+    NS_DECL_NSIINTERFACEREQUESTOR
+  private:
+    nsCOMPtr<nsIInterfaceRequestor> mCallbacks;
+  };
+  
+  /**
+   * Add an ExternalResource for aURI.  aViewer and aLoadGroup might be null
+   * when this is called if the URI didn't result in an XML document.  This
+   * function makes sure to remove the pending load for aURI, if any, from our
+   * hashtable, and to notify its observers, if any.
+   */
+  nsresult AddExternalResource(nsIURI* aURI, nsIDocumentViewer* aViewer,
+                               nsILoadGroup* aLoadGroup,
+                               nsIDocument* aDisplayDocument);
+  
+  nsClassHashtable<nsURIHashKey, ExternalResource> mMap;
+  nsRefPtrHashtable<nsURIHashKey, PendingLoad> mPendingLoads;
+  PRPackedBool mHaveShutDown;
+};
+
 // Base class for our document implementations.
 //
 // Note that this class *implements* nsIDOMXMLDocument, but it's not
@@ -802,6 +915,12 @@ public:
   virtual NS_HIDDEN_(nsresult) FinalizeFrameLoader(nsFrameLoader* aLoader);
   virtual NS_HIDDEN_(void) TryCancelFrameLoaderInitialization(nsIDocShell* aShell);
   virtual NS_HIDDEN_(PRBool) FrameLoaderScheduledToBeFinalized(nsIDocShell* aShell);
+  virtual NS_HIDDEN_(nsIDocument*)
+    RequestExternalResource(nsIURI* aURI,
+                            nsINode* aRequestingNode,
+                            ExternalResourceLoad** aPendingLoad);
+  virtual NS_HIDDEN_(void)
+    EnumerateExternalResources(nsSubDocEnumFunc aCallback, void* aData);
 
   NS_DECL_CYCLE_COLLECTION_CLASS_AMBIGUOUS(nsDocument, nsIDocument)
 
@@ -815,6 +934,11 @@ public:
 
   void DoNotifyPossibleTitleChange();
 
+  nsExternalResourceMap& ExternalResourceMap()
+  {
+    return mExternalResourceMap;
+  }
+
   void SetLoadedAsData(PRBool aLoadedAsData) { mLoadedAsData = aLoadedAsData; }
 
   nsresult CloneDocHelper(nsDocument* clone) const;
@@ -1087,6 +1211,8 @@ private:
   nsTArray<nsRefPtr<nsFrameLoader> > mFinalizableFrameLoaders;
 
   nsRevocableEventPtr<nsRunnableMethod<nsDocument> > mPendingTitleChangeEvent;
+
+  nsExternalResourceMap mExternalResourceMap;
 };
 
 #endif /* nsDocument_h___ */
diff --git a/content/base/src/nsFrameLoader.cpp b/content/base/src/nsFrameLoader.cpp
index cdb28b0de3e..8194947827d 100644
--- a/content/base/src/nsFrameLoader.cpp
+++ b/content/base/src/nsFrameLoader.cpp
@@ -727,6 +727,11 @@ nsFrameLoader::EnsureDocShell()
     return NS_ERROR_UNEXPECTED;
   }
 
+  if (doc->GetDisplayDocument()) {
+    // Don't allow subframe loads in external reference documents
+    return NS_ERROR_NOT_AVAILABLE;
+  }
+
   nsCOMPtr<nsIWebNavigation> parentAsWebNav =
     do_GetInterface(doc->GetScriptGlobalObject());
 
diff --git a/content/svg/document/src/Makefile.in b/content/svg/document/src/Makefile.in
index 17f28e5c81d..85e6653d690 100644
--- a/content/svg/document/src/Makefile.in
+++ b/content/svg/document/src/Makefile.in
@@ -54,6 +54,7 @@ REQUIRES	= \
 		  thebes \
 		  dom \
 		  webshell \
+		  docshell \
 		  htmlparser \
 		  necko \
 		  pref \
diff --git a/content/xul/content/src/nsXULElement.cpp b/content/xul/content/src/nsXULElement.cpp
index 49c5100095c..74ddb367b63 100644
--- a/content/xul/content/src/nsXULElement.cpp
+++ b/content/xul/content/src/nsXULElement.cpp
@@ -2488,7 +2488,7 @@ nsXULElement::HideWindowChrome(PRBool aShouldHide)
       return NS_ERROR_UNEXPECTED;
 
     // only top level chrome documents can hide the window chrome
-    if (doc->GetParentDocument())
+    if (!doc->IsRootDisplayDocument())
       return NS_OK;
 
     nsIPresShell *shell = doc->GetPrimaryShell();
@@ -2522,7 +2522,7 @@ nsXULElement::SetTitlebarColor(nscolor aColor, PRBool aActive)
     }
 
     // only top level chrome documents can set the titlebar color
-    if (!doc->GetParentDocument()) {
+    if (doc->IsRootDisplayDocument()) {
         nsCOMPtr<nsISupports> container = doc->GetContainer();
         nsCOMPtr<nsIBaseWindow> baseWindow = do_QueryInterface(container);
         if (baseWindow) {
diff --git a/layout/base/nsDocumentViewer.cpp b/layout/base/nsDocumentViewer.cpp
index 273347cd723..620e91bb3be 100644
--- a/layout/base/nsDocumentViewer.cpp
+++ b/layout/base/nsDocumentViewer.cpp
@@ -817,7 +817,11 @@ DocumentViewerImpl::InitInternal(nsIWidget* aParentWidget,
 
   PRBool makeCX = PR_FALSE;
   if (aDoCreation) {
-    if (aParentWidget && !mPresContext) {
+    // XXXbz this is a nasty hack to do with the fact that we create
+    // presentations both in Init() and in Show()...  Ideally we would only do
+    // it in one place (Show()) and require that callers call init(), open(),
+    // show() in that order or something.
+    if ((aParentWidget || mDocument->GetDisplayDocument()) && !mPresContext) {
       // Create presentation context
       if (mIsPageMode) {
         //Presentation context already created in SetPageMode which is calling this method
@@ -1241,12 +1245,12 @@ DocumentViewerImpl::Open(nsISupports *aState, nsISHEntry *aSHEntry)
   nsRect bounds;
   mWindow->GetBounds(bounds);
 
-  nsresult rv = InitInternal(mParentWidget, aState, bounds, PR_FALSE, PR_FALSE);
-  NS_ENSURE_SUCCESS(rv, rv);
-
   if (mDocument)
     mDocument->SetContainer(nsCOMPtr<nsISupports>(do_QueryReferent(mContainer)));
 
+  nsresult rv = InitInternal(mParentWidget, aState, bounds, PR_FALSE, PR_FALSE);
+  NS_ENSURE_SUCCESS(rv, rv);
+
   if (mPresShell)
     mPresShell->SetForwardingContainer(nsnull);
 
@@ -2101,13 +2105,14 @@ DocumentViewerImpl::CreateStyleSet(nsIDocument* aDocument,
   // The document will fill in the document sheets when we create the presshell
   
   // Handle the user sheets.
-  PRInt32 shellType = nsIDocShellTreeItem::typeContent;;
-  nsCOMPtr<nsIDocShellTreeItem> docShell(do_QueryReferent(mContainer));
-  if (docShell) {
-    docShell->GetItemType(&shellType);
-  }
+#ifdef DEBUG
+  nsCOMPtr<nsISupports> debugDocContainer = aDocument->GetContainer();
+  nsCOMPtr<nsIDocShellTreeItem> debugDocShell(do_QueryReferent(mContainer));
+  NS_ASSERTION(SameCOMIdentity(debugDocContainer, debugDocShell),
+               "Unexpected containers");
+#endif
   nsICSSStyleSheet* sheet = nsnull;
-  if (shellType == nsIDocShellTreeItem::typeChrome) {
+  if (nsContentUtils::IsInChromeDocshell(aDocument)) {
     sheet = nsLayoutStylesheetCache::UserChromeSheet();
   }
   else {
@@ -2119,7 +2124,9 @@ DocumentViewerImpl::CreateStyleSet(nsIDocument* aDocument,
 
   // Append chrome sheets (scrollbars + forms).
   PRBool shouldOverride = PR_FALSE;
-  nsCOMPtr<nsIDocShell> ds(do_QueryInterface(docShell));
+  // We don't want a docshell here for external resource docs, so just
+  // look at mContainer.
+  nsCOMPtr<nsIDocShell> ds(do_QueryReferent(mContainer));
   nsCOMPtr<nsIDOMEventTarget> chromeHandler;
   nsCOMPtr<nsIURI> uri;
   nsCOMPtr<nsICSSStyleSheet> csssheet;
@@ -2296,6 +2303,23 @@ DocumentViewerImpl::CreateDeviceContext(nsIWidget* aWidget)
 {
   NS_PRECONDITION(!mPresShell && !mPresContext && !mWindow,
                   "This will screw up our existing presentation");
+  NS_PRECONDITION(mDocument, "Gotta have a document here");
+  
+  nsIDocument* doc = mDocument->GetDisplayDocument();
+  if (doc) {
+    NS_ASSERTION(!aWidget, "Shouldn't have a widget here");
+    
+    // We want to use our display document's device context if possible
+    nsIPresShell* shell = doc->GetPrimaryShell();
+    if (shell) {
+      nsPresContext* ctx = shell->GetPresContext();
+      if (ctx) {
+        mDeviceContext = ctx->DeviceContext();
+        return NS_OK;
+      }
+    }
+  }
+  
   // Create a device context even if we already have one, since our widget
   // might have changed.
   mDeviceContext = do_CreateInstance(kDeviceContextCID);
@@ -2684,6 +2708,38 @@ SetChildFullZoom(nsIMarkupDocumentViewer* aChild, void* aClosure)
   aChild->SetFullZoom(ZoomInfo->mZoom);
 }
 
+PR_STATIC_CALLBACK(PRBool)
+SetExtResourceTextZoom(nsIDocument* aDocument, void* aClosure)
+{
+  // Would it be better to enumerate external resource viewers instead?
+  nsIPresShell* shell = aDocument->GetPrimaryShell();
+  if (shell) {
+    nsPresContext* ctxt = shell->GetPresContext();
+    if (ctxt) {
+      struct ZoomInfo* ZoomInfo = static_cast<struct ZoomInfo*>(aClosure);
+      ctxt->SetTextZoom(ZoomInfo->mZoom);
+    }
+  }
+
+  return PR_TRUE;
+}
+
+PR_STATIC_CALLBACK(PRBool)
+SetExtResourceFullZoom(nsIDocument* aDocument, void* aClosure)
+{
+  // Would it be better to enumerate external resource viewers instead?
+  nsIPresShell* shell = aDocument->GetPrimaryShell();
+  if (shell) {
+    nsPresContext* ctxt = shell->GetPresContext();
+    if (ctxt) {
+      struct ZoomInfo* ZoomInfo = static_cast<struct ZoomInfo*>(aClosure);
+      ctxt->SetFullZoom(ZoomInfo->mZoom);
+    }
+  }
+
+  return PR_TRUE;
+}
+
 NS_IMETHODIMP
 DocumentViewerImpl::SetTextZoom(float aTextZoom)
 {
@@ -2706,6 +2762,9 @@ DocumentViewerImpl::SetTextZoom(float aTextZoom)
       pc->SetTextZoom(aTextZoom);
   }
 
+  // And do the external resources
+  mDocument->EnumerateExternalResources(SetExtResourceTextZoom, &ZoomInfo);
+
   batch.EndUpdateViewBatch(NS_VMREFRESH_NO_SYNC);
   
   return NS_OK;
@@ -2737,6 +2796,9 @@ DocumentViewerImpl::SetFullZoom(float aFullZoom)
     pc->SetFullZoom(aFullZoom);
   }
 
+  // And do the external resources
+  mDocument->EnumerateExternalResources(SetExtResourceFullZoom, &ZoomInfo);
+
   batch.EndUpdateViewBatch(NS_VMREFRESH_NO_SYNC);
 
   return NS_OK;
diff --git a/layout/generic/nsFrameFrame.cpp b/layout/generic/nsFrameFrame.cpp
index c2672e3cb29..1c371252070 100644
--- a/layout/generic/nsFrameFrame.cpp
+++ b/layout/generic/nsFrameFrame.cpp
@@ -555,9 +555,11 @@ nsSubDocumentFrame::Reflow(nsPresContext*          aPresContext,
     innerSize.height -= aReflowState.mComputedBorderPadding.TopBottom();
   }
 
-  nsIViewManager* vm = mInnerView->GetViewManager();
-  vm->MoveViewTo(mInnerView, offset.x, offset.y);
-  vm->ResizeView(mInnerView, nsRect(nsPoint(0, 0), innerSize), PR_TRUE);
+  if (mInnerView) {
+    nsIViewManager* vm = mInnerView->GetViewManager();
+    vm->MoveViewTo(mInnerView, offset.x, offset.y);
+    vm->ResizeView(mInnerView, nsRect(nsPoint(0, 0), innerSize), PR_TRUE);
+  }
 
   // Determine if we need to repaint our border, background or outline
   CheckInvalidateSizeChange(aDesiredSize);
diff --git a/layout/generic/nsObjectFrame.cpp b/layout/generic/nsObjectFrame.cpp
index 52be4b169c8..ea38bd85a94 100644
--- a/layout/generic/nsObjectFrame.cpp
+++ b/layout/generic/nsObjectFrame.cpp
@@ -609,7 +609,9 @@ nsObjectFrame::Init(nsIContent*      aContent,
                     nsIFrame*        aParent,
                     nsIFrame*        aPrevInFlow)
 {
-  mPreventInstantiation = PR_FALSE;
+  NS_PRECONDITION(aContent, "How did that happen?");
+  mPreventInstantiation =
+    (aContent->GetCurrentDoc()->GetDisplayDocument() != nsnull);
 
   PR_LOG(nsObjectFrameLM, PR_LOG_DEBUG,
          ("Initializing nsObjectFrame %p for content %p\n", this, aContent));
@@ -620,7 +622,9 @@ nsObjectFrame::Init(nsIContent*      aContent,
 void
 nsObjectFrame::Destroy()
 {
-  NS_ASSERTION(!mPreventInstantiation, "about to crash due to bug 136927");
+  NS_ASSERTION(!mPreventInstantiation ||
+               mContent && mContent->GetCurrentDoc()->GetDisplayDocument(),
+               "about to crash due to bug 136927");
 
   // we need to finish with the plugin before native window is destroyed
   // doing this in the destructor is too late.
@@ -1718,6 +1722,7 @@ nsObjectFrame::Instantiate(const char* aMimeType, nsIURI* aURI)
     return rv;
   mInstanceOwner->SetPluginHost(pluginHost);
 
+  NS_ASSERTION(!mPreventInstantiation, "Say what?");
   mPreventInstantiation = PR_TRUE;
 
   rv = InstantiatePlugin(pluginHost, aMimeType, aURI);