131762 - can open multiple occurrences of download manager. r=hixie sr=ben

xpfe/components/download-manager/src/Makefile.in

@@ -39,6 +39,7 @@ REQUIRES  = xpcom \
             intl \
             windowwatcher \
             webbrowserpersist \
+            appshell \
             dom \
             $(NULL)
 CPPSRCS   = \

xpfe/components/download-manager/src/makefile.win

@@ -30,6 +30,7 @@ REQUIRES	= xpcom \
 		  intl \
       windowwatcher \
 		  webbrowserpersist \
+      appshell \
 		  dom \
 		  $(NULL)
 

xpfe/components/download-manager/src/nsDownloadManager.cpp

@@ -54,6 +54,7 @@
 #include "nsIWebBrowserPersist.h"
 #include "nsIWindowWatcher.h"
 #include "nsIStringBundle.h"
+#include "nsIWindowMediator.h"
 
 /* Outstanding issues/todo:
  * 1. Implement pause/resume.
@@ -638,9 +639,18 @@ nsDownloadManager::Open(nsIDOMWindow* aParent)
   // if this fails, it fails -- continue.
   AssertProgressInfo();
   
+  //check for an existing manager window and focus it
+  nsresult rv;
+  nsCOMPtr<nsIWindowMediator> wm = do_GetService("@mozilla.org/rdf/datasource;1?name=window-mediator", &rv);
+  if (NS_FAILED(rv)) return rv;
+
+  nsCOMPtr<nsIDOMWindowInternal> recentWindow;
+  wm->GetMostRecentWindow(NS_LITERAL_STRING("Download:Manager").get(), getter_AddRefs(recentWindow));
+  if (recentWindow)
+    return recentWindow->Focus();
+
   // if we ever have the capability to display the UI of third party dl managers,
   // we'll open their UI here instead.
-  nsresult rv;
   nsCOMPtr<nsIWindowWatcher> ww = do_GetService("@mozilla.org/embedcomp/window-watcher;1", &rv);
   if (NS_FAILED(rv)) return rv;