Land Recent QUIC Changes.

Land Recent QUIC Changes.

Add a new QUIC common cert set to reflect the new GIA cert.

Also rename the existing common cert set *.inc files.

Merge internal change: 78450265
https://codereview.chromium.org/683343002/

Removes QuicTcpCongestionWindow type and adds a new QuicPacketCount
type.

The CL also moves to using QuicPacketCount instead of
QuicTcpCongestionWindow in TCP congestion control code. Using a
QuicPacketCount type makes it obvious for congestion control
computations that a variable of this type needs to be converted when
comparing with other congestion control variables (such as
|bytes_in_flight|) that are maintained as QuicByteCount. As a type,
QuicTcpCongestionWindow currently doesn't seem to have any other
semantic value.

Merge internal change: 78399967
https://codereview.chromium.org/644853004/

Fix flaky test in QuicSessionTest. Port of
https://codereview.chromium.org/669963003/ to internal source tree.

Merge internal change: 78351892

This CL was already in chromium except for small comment change.
https://codereview.chromium.org/684783006/

Stop sending QUIC SCUP message immediately after handshake.

Merge internal change: 78296626
https://codereview.chromium.org/684983002/

Delete rolled out FLAGS_quic_store_cached_network_params_from_chlo

Merge internal change: 78276864
https://codereview.chromium.org/669663004/

Modifies RTT code to use uncorrected measured rtt for min_rtt and to
only correct for ack_delay when recording smoothed_rtt and when
ack_delay is sane.

Merge internal change: 78269418
https://codereview.chromium.org/685893002/

Flag protect enabling of QUIC's BBR congestion control algorithm.

Merge internal change: 78229291
https://codereview.chromium.org/687643004/

Further simplify QUIC's UnackedPacketMap now that the interface is
unified on AddSentPacket.

Merge internal change: 78219252
https://codereview.chromium.org/685883004/

R=rch@chromium.org,
TBR=mkosiba@chromium.org, mnaganov@chromium.org

Review URL: https://codereview.chromium.org/689483002

Cr-Commit-Position: refs/heads/master@{#301825}