Use SessionStore.promiseInitialized() to avoid race condition in "about:home" (#774)

* Use SessionStore.promiseInitialized() to avoid race condition in "about:home"

* Improve code style of [d6c3adb91c9f29786f8ed8d93baa14c076494017]

1 files changed, 12 insertions, 5 deletions

diff --git a/application/palemoon/base/content/browser.js b/application/palemoon/base/content/browser.js
index 5cf43850ae..4167f186c4 100644
--- a/application/palemoon/base/content/browser.js
+++ b/application/palemoon/base/content/browser.js
@@ -2421,11 +2421,18 @@ function BrowserOnAboutPageLoad(doc) {
   /* === about:home === */
 
   if (doc.documentURI.toLowerCase() == "about:home") {
-    let ss = Components.classes["@mozilla.org/browser/sessionstore;1"].
-             getService(Components.interfaces.nsISessionStore);
-    if (ss.canRestoreLastSession &&
-        !PrivateBrowsingUtils.isWindowPrivate(window))
-      doc.getElementById("launcher").setAttribute("session", "true");
+    if (!PrivateBrowsingUtils.isWindowPrivate(window)) {
+      let wrapper = {};
+      Cu.import("resource:///modules/sessionstore/SessionStore.jsm", wrapper);
+      let ss = wrapper.SessionStore;
+      ss.promiseInitialized.then(function() {
+        if (ss.canRestoreLastSession) {
+          doc.getElementById("launcher").setAttribute("session", "true");
+        }
+      }).then(null, function onError(x) {
+        Cu.reportError("Error in SessionStore init while processing 'about:home': " + x);
+      });
+    }
 
     // Inject search engine and snippets URL.
     let docElt = doc.documentElement;