Bug 1447719 - Set browser.startup.blankWindow to true on Windows and Linux, r=mconley.

browser/app/profile/firefox.js

@@ -260,7 +260,12 @@ pref("browser.startup.homepage",            "chrome://branding/locale/browsercon
 pref("browser.startup.firstrunSkipsHomepage", true);
 
 // Show an about:blank window as early as possible for quick startup feedback.
+#ifdef XP_MACOSX
+// Disabled on Mac because the bouncing dock icon already provides feedback.
 pref("browser.startup.blankWindow", false);
+#else
+pref("browser.startup.blankWindow", true);
+#endif
 
 pref("browser.slowStartup.notificationDisabled", false);
 pref("browser.slowStartup.timeThreshold", 20000);

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

@@ -122,6 +122,10 @@ const startupPhases = {
   }},
 };
 
+if (Services.prefs.getBoolPref("browser.startup.blankWindow")) {
+  startupPhases["before profile selection"].whitelist.components.add("XULStore.js");
+}
+
 if (!gBrowser.selectedBrowser.isRemoteBrowser) {
   // With e10s disabled, Places and RecentWindow.jsm (from a
   // SessionSaver.jsm timer) intermittently get loaded earlier. Likely