Bug 1135303 - Don't warn when closing multiple tabs if sessionstore can undo close the requested amount of tabs. r=Gijs,mikedeboer

Differential Revision: https://phabricator.services.mozilla.com/D17858

--HG--
extra : moz-landing-system : lando

browser/app/profile/firefox.js

@@ -823,7 +823,7 @@ pref("browser.sessionstore.idleDelay", 180000); // 3 minutes
 // 0 = everywhere, 1 = unencrypted sites, 2 = nowhere
 pref("browser.sessionstore.privacy_level", 0);
 // how many tabs can be reopened (per window)
-pref("browser.sessionstore.max_tabs_undo", 10);
+pref("browser.sessionstore.max_tabs_undo", 25);
 // how many windows can be reopened (per session) - on non-OS X platforms this
 // pref may be ignored when dealing with pop-up windows to ensure proper startup
 pref("browser.sessionstore.max_windows_undo", 3);

browser/base/content/tabbrowser.js

@@ -2676,6 +2676,12 @@ window._gBrowser = {
     if (!shouldPrompt)
       return true;
 
+    const maxTabsUndo = Services.prefs.getIntPref("browser.sessionstore.max_tabs_undo");
+    if (aCloseTabs != this.closingTabsEnum.ALL &&
+        tabsToClose <= maxTabsUndo) {
+      return true;
+    }
+
     var ps = Services.prompt;
 
     // default to true: if it were false, we wouldn't get this far