update a few menu.popup() calls to use the new API

lib/browser/api/web-contents.js

@@ -293,7 +293,12 @@ WebContents.prototype._init = function () {
   this.on('pepper-context-menu', function (event, params, callback) {
     // Access Menu via electron.Menu to prevent circular require.
     const menu = electron.Menu.buildFromTemplate(params.menu)
-    menu.popup(event.sender.getOwnerBrowserWindow(), params.x, params.y, callback)
+    menu.popup({
+      window: event.sender.getOwnerBrowserWindow(),
+      x: params.x,
+      y: params.y,
+      callback: callback
+    })
   })
 
   // The devtools requests the webContents to reload.