[SPDY] Incorporate latest framing changes from HTTP2 into SPDY 4 as SPDY 4a2.
Removes support for SPDY 4a1.

Remove --enable-spdy4 flag for now (until we get test
coverage).

This lands server change 45362310.

BUG=230124
TBR=jam@chromium.org

Review URL: https://chromiumcodereview.appspot.com/14189003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@200342 0039d316-1c4b-4281-b951-d872f2087c98
21 files changed