Update a few JumpList comments

chrome/browser/win/jumplist.h

 // 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.
 
 #ifndef CHROME_BROWSER_WIN_JUMPLIST_H_
 #define CHROME_BROWSER_WIN_JUMPLIST_H_
 
 #include <stddef.h>
 
 #include <list>
@@ skipping 101 matching lines @@
 
   // Terminate the jumplist: cancel any pending updates and stop observing
   // the Profile and its services. This must be called before the |profile_|
   // is destroyed.
   void Terminate();
 
   // RefcountedKeyedService:
   void ShutdownOnUIThread() override;
 
   // Returns true if the custom JumpList is enabled.
-  // The custom jumplist works only on Windows 7 and above.
   static bool Enabled();
 
  private:
   friend JumpListFactory;
   explicit JumpList(Profile* profile);  // Use JumpListFactory instead
   ~JumpList() override;
 
-  // The AddTab and AddWindow functions are copied from the
-  // RecentlyClosedTabsHandler class for compatibility with the new-tab page.
-
   // Adds a new ShellLinkItem for |tab| to |data| provided that doing so will
   // not exceed |max_items|.
   bool AddTab(const sessions::TabRestoreService::Tab& tab,
               size_t max_items,
               JumpListData* data);
 
   // Adds a new ShellLinkItem for each tab in |window| to |data| provided that
   // doing so will not exceed |max_items|.
   void AddWindow(const sessions::TabRestoreService::Window& window,
                  size_t max_items,
@@ skipping 66 matching lines @@
   // JumpListIconsOld directory.
   scoped_refptr<base::SequencedTaskRunner> delete_jumplisticons_task_runner_;
 
   // For callbacks may be run after destruction.
   base::WeakPtrFactory<JumpList> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(JumpList);
 };
 
 #endif  // CHROME_BROWSER_WIN_JUMPLIST_H_