Revert 226390 "Land Recent QUIC changes."

Revert 226390 "Land Recent QUIC changes."

> Land Recent QUIC changes.
>
> Fixing minor nits (added using std::pair).
>
> Merge internal change: 53257699
>
> Increasing the maximum tcp congestion window to 200 packets from 100.
>
> Merge internal change: 53185276
>
> Add a DCHECK to ensure the sent packet sequence number never goes down
> and separate the send alarm into a send alarm and a resume writes
> alarm to be used when the socket is still writable an there may be
> more pending data to write.
>
> Merge internal change: 53050471
>
> Merged quic_epoll_connection_helper_test.cc from internal code.
>
> Minor nit fixes.
>
> Merge internal change: 53048224
>
> Move QuicAckNotifierManager from QuicConnection to
> QuicSentPacketManager.
>
> Merge internal change: 53036185
>
> R=jar@chromium.org, rch@chromium.org, wtc@chromium.org
>
> Review URL: https://codereview.chromium.org/25443002

TBR=rtenneti@chromium.org
BUG=303981

Review URL: https://codereview.chromium.org/25727012

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@227044 0039d316-1c4b-4281-b951-d872f2087c98