Land Recent QUIC Changes.

QUIC Refactor to move the call to OnPacketAbandoned() for
retransmissions into QuicCongestionManager.

Merge internal change: 57233749
https://codereview.chromium.org/85463010/


Rename two methods in SendAlgorithmInterface
   * OnIncomingAck -> OnPacketAcked
   * OnIncomingLoss -> OnPacketLost

Merge internal change: 57120421
https://codereview.chromium.org/85663006/


Implement Early Retransmit(RFC5827) in QUIC's TCP congestion control.

Merge internal change: 57097940
https://codereview.chromium.org/85663005/


De-flake internal end_to_end_tests when pacing is used.

Adds a new HasQueuedData method, and removes NumWriteBlockedStreams
method to QuicSession, which is only called from tests.

Merge internal change: 57090300
https://codereview.chromium.org/84723005/


Send the server's supported QUIC versions in the SHLO. Send the client's
supported QUIC version in the CHLO.  Detect downgrade attacks.

Add QUIC versions to the QUIC handshake messages.

Merge internal change: 57057343
https://codereview.chromium.org/85773006/


Change QUIC's nack counting to be based on the gap between the missing
packet and the largest observed, instead of the number of ack frames
processed.

Merge internal change: 57031841
https://codereview.chromium.org/85383010/


QUIC - sync'ing chromium and internal source. Minor clean up of the code.

Merge internal change: 57264741
https://codereview.chromium.org/86483007/

R=rch@chromium.org

Review URL: https://codereview.chromium.org/87013002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@237410 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 237410