Dynamic updating recent menu for tabs from other devices.

chrome/browser/ui/toolbar/app_menu_model.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/toolbar/app_menu_model.h"
 
 #include <algorithm>
 #include <cmath>
 
 #include "base/command_line.h"
@@ skipping 699 matching lines @@
       IsCommandIdVisible(IDC_UPGRADE_DIALOG))
     AddSeparator(ui::NORMAL_SEPARATOR);
 
   AddItemWithStringId(IDC_NEW_TAB, IDS_NEW_TAB);
   AddItemWithStringId(IDC_NEW_WINDOW, IDS_NEW_WINDOW);
   if (ShouldShowNewIncognitoWindowMenuItem())
     AddItemWithStringId(IDC_NEW_INCOGNITO_WINDOW, IDS_NEW_INCOGNITO_WINDOW);
   AddSeparator(ui::NORMAL_SEPARATOR);
 
   if (!browser_->profile()->IsOffTheRecord()) {
-    recent_tabs_sub_menu_model_.reset(new RecentTabsSubMenuModel(provider_,
-                                                                 browser_,
-                                                                 NULL));
+    recent_tabs_sub_menu_model_ =
+        base::MakeUnique<RecentTabsSubMenuModel>(provider_, browser_);
     AddSubMenuWithStringId(IDC_RECENT_TABS_MENU, IDS_HISTORY_MENU,
                            recent_tabs_sub_menu_model_.get());
   }
   AddItemWithStringId(IDC_SHOW_DOWNLOADS, IDS_SHOW_DOWNLOADS);
   if (!browser_->profile()->IsGuestSession()) {
     bookmark_sub_menu_model_.reset(new BookmarkSubMenuModel(this, browser_));
     AddSubMenuWithStringId(IDC_BOOKMARKS_MENU, IDS_BOOKMARKS_MENU,
                            bookmark_sub_menu_model_.get());
   }
 
@@ skipping 130 matching lines @@
                        browser_->tab_strip_model()->GetActiveWebContents())
                        ->GetZoomPercent();
   }
   zoom_label_ = base::FormatPercent(zoom_percent);
 }
 
 void AppMenuModel::OnZoomLevelChanged(
     const content::HostZoomMap::ZoomLevelChange& change) {
   UpdateZoomControls();
 }