Revert 165922 "Block WebSocket connection to insecure server fro..."

The CL breaks some WebSocket applications and we want more time to announce.

> Block WebSocket connection to insecure server from secure page.
> 
> The W3C WebSocket API specifies that the browser must throw an SecurityError
> exception if the requested URL is insecure and the origin is secure.
> 
> BUG=85271
> R=tyoshino, abarth
> 
> Review URL: https://codereview.chromium.org/143763002

TBR=yhirano@chromium.org

Review URL: https://codereview.chromium.org/147923009

git-svn-id: svn://svn.chromium.org/blink/trunk@165999 bbb929c8-8fbe-4397-9dbb-9b2b20218538