Revert 228145 "Land Recent QUIC changes."

Revert 228145 "Land Recent QUIC changes."

> Land Recent QUIC changes.
>
> Remove unused IsWriteBlocked method from QuicConnectionHelperInterface.
>
> Merge internal change: 53803217
>
> Add missing QUIC_VERSION_Q011 case in QuicVersionToString.
>
> Merge internal change: 53749976
>
> QUIC: don't ignore SetKey and SetNoncePrefix return values.
>
> This change causes failures to set the AES-GCM key and nonce to bubble
> up and kill the connection. I don't think that we've had any failures,
> but you never know and it would be bad to, say, start transmitting
> plaintext or something because we didn't notice that we failed to set
> a key.
>
> (The OpenSSL AEAD API doesn't actually let that happen: it zeros the
> output buffer on any failure, but things might change in the future.)
>
> (This is a follow up from a previous CL which altered our AES-128-GCM
> implementation.)
>
> Merge internal change: 53742674
>
> Reduce the length of the QUIC null encryption auth hash from 16 bytes to
> 12 bytes to match the length of the AES auth hash.
>
> Merge internal change: 53693995
>
> R=rch@chromium.org
>
> Review URL: https://codereview.chromium.org/26739002

TBR=rtenneti@chromium.org

Review URL: https://codereview.chromium.org/27022003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228206 0039d316-1c4b-4281-b951-d872f2087c98