Bug 1485629 - Disable the early blank window when using a non-default theme. r=florian

browser/base/content/test/performance/browser_startup.js

@@ -121,7 +121,9 @@ const startupPhases = {
   }},
 };
 
-if (Services.prefs.getBoolPref("browser.startup.blankWindow")) {
+if (Services.prefs.getBoolPref("browser.startup.blankWindow") &&
+    Services.prefs.getCharPref("lightweightThemes.selectedThemeID") ==
+      "default-theme@mozilla.org") {
   startupPhases["before profile selection"].whitelist.components.add("XULStore.js");
 }
 

browser/components/nsBrowserGlue.js

@@ -308,6 +308,12 @@ let ACTORS = {
   if (!Services.prefs.getBoolPref("browser.startup.blankWindow", false))
     return;
 
+  // Until bug 1450626 and bug 1488384 are fixed, skip the blank window when
+  // using a non-default theme.
+  if (Services.prefs.getCharPref("lightweightThemes.selectedThemeID", "") !=
+        "default-theme@mozilla.org")
+    return;
+
   let store = Services.xulStore;
   let getValue = attr =>
     store.getValue(AppConstants.BROWSER_CHROME_URL, "main-window", attr);