Work done by Vidur and me. Added a FlushPendingNotifications() method to the document. This method flushes the pending content notifications from the content sink and the pending reflow notifications from the pres shell. This code is turned off for now so that it can be tested more thoroughly by Vidur and me.

parser/htmlparser/robot/nsRobotSink.cpp

@@ -83,6 +83,7 @@ public:
   NS_IMETHOD WillInterrupt(void) { return NS_OK; }
   NS_IMETHOD WillResume(void) { return NS_OK; }
   NS_IMETHOD SetParser(nsIParser* aParser) { return NS_OK; }
+  NS_IMETHOD FlushPendingNotifications() { return NS_OK; }
 
   NS_IMETHOD DoFragment(PRBool aFlag);
   NS_IMETHOD BeginContext(PRInt32 aPosition){ return NS_OK; }