From 8bb48e2a53c80efd922911ae770dad09ca8de3d8 Mon Sep 17 00:00:00 2001
From: Christopher Willis-Ford <cwillisf@media.mit.edu>
Date: Tue, 31 Oct 2017 13:00:19 -0700
Subject: [PATCH] Add built-in extension "URL" to _loadedExtensions

Dupe prevention works better when you actually record the necessary
info...
---
 src/extension-support/extension-manager.js | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/extension-support/extension-manager.js b/src/extension-support/extension-manager.js
index d9dc3603e..ef3d56aa8 100644
--- a/src/extension-support/extension-manager.js
+++ b/src/extension-support/extension-manager.js
@@ -116,7 +116,9 @@ class ExtensionManager {
 
             const extension = builtinExtensions[extensionURL];
             const extensionInstance = new extension(this.runtime);
-            return this._registerInternalExtension(extensionInstance);
+            return this._registerInternalExtension(extensionInstance).then(() => {
+                this._loadedExtensions.add(extensionURL);
+            });
         }
 
         return new Promise((resolve, reject) => {