Dynamic labels for the undo/redo context menus in bookmark bar.

The labels for the Undo and Redo context menu items change based on
the next action. For example, when a bookmark is deleted the menu item
will show as "Undo delete" and "Redo delete".

This is visible with the switch enable-bookmark-undo and found in the
bookmark bar context menu.

BUG=126092

Review URL: https://codereview.chromium.org/115233005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@241309 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 241309