Remove HTTP/0.9 support from HttpStreamParser.

HTTP/0.9 is an ancient protocol with some fundamental design problems.
This CL remove support for it, while leaving most of the code needed to
support HTTP/0.9 in place, in case this has to be reverted late in the
game, or we decide to add a (temporary) enterprise policy to enable it.

BUG=624462

Review-Url: https://codereview.chromium.org/2144803002
Cr-Commit-Position: refs/heads/master@{#405687}
11 files changed