WebSocketBasicHandshakeStream performs the WebSocket standard RFC6455 WebSocket handshake over plain-text and SSL connections.

Design doc at:
https://docs.google.com/a/chromium.org/document/d/1r7dQDA9AQBD_kOk-z-yMi0WgLQZ-5m7psMO5pYLFUL8/edit

Tests are in a separate CL: https://codereview.chromium.org/64133006/
BUG=303568
TEST=net_unittests --gtest_filter=WebSocket*

Review URL: https://codereview.chromium.org/25417005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237553 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237553