Use ES6 Promise in Bookmark manager instead of cr.Promise

BUG=None

Review URL: https://codereview.chromium.org/137143004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247091 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247091