[hack] Add missing file from "Implements file watcher on Windows."
[hack] Add missing file from "Implements file watcher on Windows."

Summary: This was supposed to be part of
https://github.com/facebook/hhvm/pull/6135, but I messed up the manual patch
and commit :(

Reviewed By: @JoelMarcey

Differential Revision: D2505782

AprilArcus/flow,claudiopro/flow,cesarandreu/flow,chenglou/flow,chenglou/flow,jamesgpearce/flow,AprilArcus/flow,popham/flow,samwgoldman/flow,claudiopro/flow,ForbesLindesay/flow,gabro/flow,shiftcars/flow,AgentME/flow,shiftcars/flow,facebook/flow,ylu1317/flow,TiddoLangerak/flow,chenglou/flow,OCamlPro/flow,mroch/flow,nmote/flow,claudiopro/flow,mroch/flow,cesarandreu/flow,d14b3l/flow,ylu1317/flow,ylu1317/flow,cesarandreu/flow,samwgoldman/flow,gabelevi/flow,gabelevi/flow,facebook/flow,jdelStrother/flow,shiftcars/flow,gabro/flow,jgrund/flow,samwgoldman/flow,jgrund/flow,mroch/flow,JonathanUsername/flow,facebook/flow,jeffmo/flow,shiftcars/flow,gabelevi/flow,d14b3l/flow,d14b3l/flow,ylu1317/flow,claudiopro/flow,AprilArcus/flow,samwgoldman/flow,graue/flow,JonathanUsername/flow,graue/flow,gabelevi/flow,TiddoLangerak/flow,fletcherw/flow,graue/flow,samwgoldman/flow,jdelStrother/flow,chenglou/flow,cesarandreu/flow,shiftcars/flow,chenglou/flow,mroch/flow,OCamlPro/flow,AprilArcus/flow,jamesgpearce/flow,jamesgpearce/flow,JonathanUsername/flow,AgentME/flow,jeffmo/flow,ylu1317/flow,AgentME/flow,jdelStrother/flow,OCamlPro/flow,facebook/flow,JonathanUsername/flow,TiddoLangerak/flow,popham/flow,jgrund/flow,nmote/flow,JonathanUsername/flow,gabro/flow,gabro/flow,MichaelDeBoey/flow,ForbesLindesay/flow,JonathanUsername/flow,MichaelDeBoey/flow,jgrund/flow,chenglou/flow,JonathanUsername/flow,graue/flow,OCamlPro/flow,mroch/flow,mroch/flow,nmote/flow,gabelevi/flow,AprilArcus/flow,samwgoldman/flow,popham/flow,jamesgpearce/flow,facebook/flow,fletcherw/flow,nmote/flow,graue/flow,gabro/flow,samwgoldman/flow,d14b3l/flow,mroch/flow,popham/flow,nmote/flow,graue/flow,ForbesLindesay/flow,MichaelDeBoey/flow,TiddoLangerak/flow,popham/flow,AprilArcus/flow,d14b3l/flow,ForbesLindesay/flow,ForbesLindesay/flow,facebook/flow,jdelStrother/flow,fletcherw/flow,gabro/flow,facebook/flow,fletcherw/flow,popham/flow,fletcherw/flow,jeffmo/flow,MichaelDeBoey/flow,claudiopro/flow,nmote/flow,Eyyub/flow,gabelevi/flow,d14b3l/flow,jgrund/flow,ForbesLindesay/flow,popham/flow,Eyyub/flow,jamesgpearce/flow,jeffmo/flow,jdelStrother/flow,jeffmo/flow,Eyyub/flow,MichaelDeBoey/flow,jamesgpearce/flow,jdelStrother/flow,Eyyub/flow,jgrund/flow,jamesgpearce/flow,TiddoLangerak/flow,gabelevi/flow,shiftcars/flow,fletcherw/flow,jeffmo/flow,AgentME/flow,AgentME/flow,nmote/flow