Fixes regression from changes to restore tabs

chrome/browser/ui/views/frame/system_menu_model_delegate.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/ui/views/frame/system_menu_model_delegate.h"
 
 #include "base/prefs/pref_service.h"
 #include "chrome/app/chrome_command_ids.h"
 #include "chrome/browser/command_updater.h"
 #include "chrome/browser/profiles/profile.h"
@@ skipping 19 matching lines @@
     case IDC_USE_SYSTEM_TITLE_BAR: {
       PrefService* prefs = browser_->profile()->GetPrefs();
       return !prefs->GetBoolean(prefs::kUseCustomChromeFrame);
     }
     default:
       return false;
   }
 }
 
 bool SystemMenuModelDelegate::IsCommandIdEnabled(int command_id) const {
-  return chrome::IsCommandEnabled(browser_, command_id);
+  if (!chrome::IsCommandEnabled(browser_, command_id))
+    return false;
+
+  if (command_id != IDC_RESTORE_TAB)
+    return true;
+
+  // chrome::IsCommandEnabled(IDC_RESTORE_TAB) returns true if TabRestoreService
+  // hasn't been loaded yet. Return false if this is the case as we don't have
+  // a good way to dynamically update the menu when TabRestoreService finishes
+  // loading.
+  // TODO(sky): add a way to update menu.
+  TabRestoreService* trs =
+      TabRestoreServiceFactory::GetForProfile(browser_->profile());
+  if (!trs->IsLoaded()) {
+    trs->LoadTabsFromLastSession();
+    return false;
+  }
+  return true;
 }
 
 bool SystemMenuModelDelegate::GetAcceleratorForCommandId(int command_id,
                                              ui::Accelerator* accelerator) {
   return provider_->GetAcceleratorForCommandId(command_id, accelerator);
 }
 
 bool SystemMenuModelDelegate::IsItemForCommandIdDynamic(int command_id) const {
   return command_id == IDC_RESTORE_TAB;
 }
 
 base::string16 SystemMenuModelDelegate::GetLabelForCommandId(
     int command_id) const {
   DCHECK_EQ(command_id, IDC_RESTORE_TAB);
 
   int string_id = IDS_RESTORE_TAB;
   if (IsCommandIdEnabled(command_id)) {
     TabRestoreService* trs =
         TabRestoreServiceFactory::GetForProfile(browser_->profile());
-    if (trs && trs->entries().front()->type == TabRestoreService::WINDOW)
+    trs->LoadTabsFromLastSession();
+    if (trs && !trs->entries().empty() &&
+        trs->entries().front()->type == TabRestoreService::WINDOW)
       string_id = IDS_RESTORE_WINDOW;
   }
   return l10n_util::GetStringUTF16(string_id);
 }
 
 void SystemMenuModelDelegate::ExecuteCommand(int command_id, int event_flags) {
   chrome::ExecuteCommand(browser_, command_id);
 }