Delete last bit of stashed message port implementation from blink.
Delete last bit of stashed message port implementation from blink.

It's not entirely clear what the future of navigator.connect is, but stashed
ports is definitely not it.

[1/3] https://codereview.chromium.org/1248003003, deleting most of the blink side of the code
[2/3] https://codereview.chromium.org/1248763005, deletes the content side
[3/3] This patch, deletes the rest of the blink code

BUG=483108

Review URL: https://codereview.chromium.org/1248893003

git-svn-id: bf5cd6ccde378db821296732a091cfbcf5285fbd@199330 bbb929c8-8fbe-4397-9dbb-9b2b20218538

Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk,Pluto-tv/blink-crosswalk