URILoader now will invoke the unkown content handler when the DoContent call fails. This clears the way for the new docShell creation of the content viewer code to land. I'm actually checking this in for mcott. b=13374 r=me a=jevering

uriloader/base/nsURILoader.cpp

@@ -43,6 +43,9 @@
 #include "nsXPIDLString.h"
 #include "nsString.h"
 
+#include "nsIDOMWindow.h"
+#include "nsIUnkContentTypeHandler.h"
+
 static NS_DEFINE_CID(kURILoaderCID, NS_URI_LOADER_CID);
 static NS_DEFINE_CID(kStreamConverterServiceCID, NS_STREAMCONVERTERSERVICE_CID);
 
@@ -166,9 +169,10 @@ public:
 
 protected:
     virtual ~nsDocumentOpenInfo();
-
     nsDocumentOpenInfo* Clone();
 
+    nsresult InvokeUnknownContentHandler(nsIChannel * aChannel, const char * aContentType, nsIDOMWindow * aDomWindow);
+
 protected:
     nsCOMPtr<nsIURIContentListener> m_contentListener;
     nsCOMPtr<nsIStreamListener> m_targetStreamListener;
@@ -387,6 +391,12 @@ nsresult nsDocumentOpenInfo::DispatchContent(nsIChannel * aChannel, nsISupports
       // the listener is doing all the work from here...we are done!!!
       if (bAbortProcess) return rv;
 
+      if (NS_FAILED(rv))
+      {
+        nsCOMPtr<nsIDOMWindow> domWindow (do_GetInterface(contentListener));
+        return InvokeUnknownContentHandler(aChannel, contentType, domWindow);
+      }
+
       // okay, all registered listeners have had a chance to handle this content...
       // did one of them give us a stream listener back? if so, let's start reading data
       // into it...
@@ -396,6 +406,17 @@ nsresult nsDocumentOpenInfo::DispatchContent(nsIChannel * aChannel, nsISupports
   return rv;
 }
 
+nsresult nsDocumentOpenInfo::InvokeUnknownContentHandler(nsIChannel * aChannel, const char * aContentType, nsIDOMWindow * aDomWindow)
+{
+  NS_ENSURE_ARG(aChannel);
+  NS_ENSURE_ARG(aDomWindow);
+
+  nsCOMPtr<nsIUnknownContentTypeHandler> handler (do_GetService(NS_IUNKNOWNCONTENTTYPEHANDLER_PROGID));
+  NS_ENSURE_TRUE(handler, NS_ERROR_FAILURE);
+
+  return handler->HandleUnknownContentType( aChannel, aContentType, aDomWindow );
+}
+
 nsresult nsDocumentOpenInfo::RetargetOutput(nsIChannel * aChannel, const char * aSrcContentType, const char * aOutContentType,
                                             nsIStreamListener * aStreamListener)
 {