🍎 Add additional options for Mac's save dialog

Support additional attributes available in macOS's NSSavePanel: message,
nameFieldLabel and showsTagField

lib/browser/api/dialog.js

@@ -136,7 +136,8 @@ module.exports = {
       }
     }
 
-    let {buttonLabel, defaultPath, filters, title} = options
+    let {buttonLabel, defaultPath, filters, title, message, nameFieldLabel,
+      showsTagField} = options
 
     if (title == null) {
       title = ''
@@ -160,10 +161,27 @@ module.exports = {
       filters = []
     }
 
+    if (message == null) {
+      message = ''
+    } else if (typeof message !== 'string') {
+      throw new TypeError('Message must be a string')
+    }
+
+    if (nameFieldLabel == null) {
+      nameFieldLabel = ''
+    } else if (typeof nameFieldLabel !== 'string') {
+      throw new TypeError('Name field label must be a string')
+    }
+
+    if (showsTagField == null) {
+      showsTagField = false
+    }
+
     const wrappedCallback = typeof callback === 'function' ? function (success, result) {
       return callback(success ? result : void 0)
     } : null
     return binding.showSaveDialog(title, buttonLabel, defaultPath, filters,
+                                  message, nameFieldLabel, showsTagField,
                                   window, wrappedCallback)
   },