1 files changed, 24 insertions, 0 deletions
diff --git a/browser/modules/TransientPrefs.jsm b/browser/modules/TransientPrefs.jsm
new file mode 100644
index 000000000..30ba6a152
--- /dev/null
+++ b/browser/modules/TransientPrefs.jsm
@@ -0,0 +1,24 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+this.EXPORTED_SYMBOLS = ["TransientPrefs"];
+
+Components.utils.import("resource://gre/modules/Preferences.jsm");
+
+var prefVisibility = new Map;
+
+/* Use for preferences that should only be visible when they've been modified.
+   When reset to their default state, they remain visible until restarting the
+   application. */
+
+this.TransientPrefs = {
+  prefShouldBeVisible: function (prefName) {
+    if (Preferences.isSet(prefName))
+      prefVisibility.set(prefName, true);
+
+    return !!prefVisibility.get(prefName);
+  }
+};