re-port CHM from jdk9 to patch vulnerability described in http://cs.oswego.edu/pipermail/concurrency-interest/2013-December/012005.html
(cherry picked from commit 92af49d) [r=Maxim.Mossienko]
re-port concurrent maps from jdk9
(cherry picked from commit b9bfd33) [r=Maxim.Mossienko]
add a constructor to HtmlDocumentImpl
(cherry picked from commit 0e3e0f1 r=Oleg Sukhodolsky)