This is a regression test for crbug.com/343506. It sends one empty
message fragmented into two frames. There are pauses between the
frames to force the browser to process them individually.

Requires https://codereview.chromium.org/170383002/ in be landed in Chromium in
order to pass.

BUG=343506
TEST=this

Review URL: https://codereview.chromium.org/170393002

git-svn-id: svn://svn.chromium.org/blink/trunk@167595 bbb929c8-8fbe-4397-9dbb-9b2b20218538