Undeprecate PPAPI WebSocket

Remove the deprecation console message and documentation comments for
PPAPI WebSocket. This is mostly a straightforward revert of
https://chromium-review.googlesource.com/c/chromium/src/+/1161712/
except that the enums have been left behind.

See
https://groups.google.com/a/chromium.org/d/msg/blink-dev/lWNvY56OAYs/9IoQx_ncDQAJ
for the background and justification for undoing the deprecation.

BUG=870586

Change-Id: I436e016b98e5e6224fca420ed769420f016bf6ac
Reviewed-on: https://chromium-review.googlesource.com/c/1402306
Reviewed-by: Yutaka Hirano <yhirano@chromium.org>
Reviewed-by: Bill Budge <bbudge@chromium.org>
Reviewed-by: Nate Chapin <japhet@chromium.org>
Commit-Queue: Adam Rice <ricea@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#622756}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: dfc22b6813741d7ca31a5c0debe2201bb553b483
4 files changed