Bug 391380 - moz-icon: launches handler dialog. r=bzbarsky, sr=dmose, a=bzbarsky

modules/libpref/src/init/all.js

@@ -521,6 +521,7 @@ pref("network.protocol-handler.external.help", false);
 pref("network.protocol-handler.external.disk", false);
 pref("network.protocol-handler.external.disks", false);
 pref("network.protocol-handler.external.afp", false);
+pref("network.protocol-handler.external.moz-icon", false);
 
 // An exposed protocol handler is one that can be used in all contexts.  A
 // non-exposed protocol handler is one that can only be used internally by the

uriloader/exthandler/nsExternalHelperAppService.cpp

@@ -1136,12 +1136,15 @@ nsresult nsExternalHelperAppService::GetFileTokenForPath(const PRUnichar * aPlat
 NS_IMETHODIMP nsExternalHelperAppService::ExternalProtocolHandlerExists(const char * aProtocolScheme,
                                                                         PRBool * aHandlerExists)
 {
-  // if we've got handler info in the datasource, that means that at least one
-  // web handler exists
   nsCOMPtr<nsIHandlerInfo> handlerInfo;
   nsresult rv = GetProtocolHandlerInfo(
       nsDependentCString(aProtocolScheme), getter_AddRefs(handlerInfo));
-  if (NS_SUCCEEDED(rv)) {
+  NS_ENSURE_SUCCESS(rv, rv);
+
+  // See if we have a preferred handler app for this
+  nsCOMPtr<nsIHandlerApp> preferredApp;
+  handlerInfo->GetPreferredApplicationHandler(getter_AddRefs(preferredApp));
+  if (preferredApp) {
     *aHandlerExists = PR_TRUE;
     return NS_OK;
   }