Allow sending of empty Close frames from Blink.

net::WebSocketChannel provided no way for the renderer to send a Close
frame with no payload.

Allow the renderer to use code 1005 ("No Status Rcvd") to mean no
payload should be sent.

BUG=345683
TEST=net_unittests, layout test client-close.html

Review URL: https://codereview.chromium.org/175213002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253391 0039d316-1c4b-4281-b951-d872f2087c98
Rename ibus_keymap to ime_keymap, it's about converting from X11
keysym to javascript key strings which is not anything to do with IBus.

BUG=283612

Review URL: https://codereview.chromium.org/163883007

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@253392 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 253392