Land Recent QUIC changes.

Land Recent QUIC changes.

Pass HasRetransmittableData to the congestion manager and the send
algorithm. This allows tcp_cubic_sender to not count ACK-only packets
against the congestion window.

Merge internal change: 51829697

If a previously zombie'd QUIC stream is closed and the headers have been
decompressed, remove that entry from the zombie stream map.

Merge internal change: 51697989

Change the value used to set the sequence number with to both correctly
calculate the widest packet spread currently outstanding and fix a
DCHECK failure in EndToEnd's Uber test when packets were transmitted
sufficiently out of order that the packet being sent was less than the
last packet the peer was awaiting.

Merge internal change: 51644967

Fix a bug where frames are queued and not enough room for the next
stream frame is available, but we attempt to create a STREAM frame
anyway in ConsumeData.

Merge internal change: 51604946

Changed Delayed Ack Timer to go off before the sender's retransmission
timer goes off.

Merge internal change: 51594956

Using the priorities sent by the client, including bounds checking,
and bumping the priority of initial writes to avoid the HOL header
blocking issue.

Merge internal change: 51586426

Fix memory leak uncovered by https://codereview.chromium.org/23587004

Merge internal change: 51569066

Added logging of QUIC version negotiated.

Export number of QUIC sessions and streams for each QUIC version.

Merge internal change: 51540178

A refactor of QuicFdWrapper's writev to pass the iovec all the way to
QuicConnection, allowing better packet packing.

Merge internal change: 51530908

Enabled priorities in chrome quic streams.

R=rch@chromium.org

Review URL: https://chromiumcodereview.appspot.com/23597045

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@223880 0039d316-1c4b-4281-b951-d872f2087c98