Prevent crash when IFRAME is reframed during layout. bug=108105 r=dbaron sr=jst

git-svn-id: svn://10.0.0.236/trunk@109903 18797224-902f-48f8-a5cc-f745e15eee43

mozilla/docshell/base/nsDocShell.cpp

@@ -5862,6 +5862,15 @@ nsDocShell::GetCanvasHasFocus(PRBool *aCanvasHasFocus)
   return NS_ERROR_FAILURE;
 }
 
+/* boolean IsBeingDestroyed (); */
+NS_IMETHODIMP 
+nsDocShell::IsBeingDestroyed(PRBool *aDoomed)
+{
+  NS_ENSURE_ARG(aDoomed);
+  *aDoomed = mIsBeingDestroyed;
+  return NS_OK;
+}
+
 //*****************************************************************************
 //***    nsRefreshTimer: Object Management
 //*****************************************************************************

mozilla/docshell/base/nsIDocShell.idl

@@ -276,5 +276,10 @@ interface nsIDocShell : nsISupports
    * attribute to access the loadtype  for the document
    */
   attribute unsigned long  loadType;
+
+  /*
+   * returns true if the docshell is being destroyed, false otherwise
+   */
+  boolean IsBeingDestroyed();
 };