Delay a QUIC server's use of the FORWARD_SECURE encrypter until the

Delay a QUIC server's use of the FORWARD_SECURE encrypter until the
client has had a chance to start using it.

Protected by FLAGS_enable_quic_delay_forward_security.

When the forward secure encrypter is available, don't use it until one
of two things happens:
1) the peers starts sending forward secure encrypted packets
2) 2 round trips worth of packets have been sent, in case something
   (MitM?) is preventing the peer from using forward secure encryption.

Merge internal change: 78801773

R=rch@chromium.org

[Ryan Hamilton, 2014-11-03 18:09:34]

lgtm

https://codereview.chromium.org/698703003/diff/1/net/quic/quic_flags.cc
File net/quic/quic_flags.cc (right):

https://codereview.chromium.org/698703003/diff/1/net/quic/quic_flags.cc#newco...
net/quic/quic_flags.cc:64: bool FLAGS_enable_quic_delay_forward_security =
false;
I think you can go ahead and set this to true. It shouldn't actually matter
client-side so it might be worth turning it on to exercise the code path.

[ramant (doing other things), 2014-11-03 18:28:52]

https://codereview.chromium.org/698703003/diff/1/net/quic/quic_flags.cc
File net/quic/quic_flags.cc (right):

https://codereview.chromium.org/698703003/diff/1/net/quic/quic_flags.cc#newco...
net/quic/quic_flags.cc:64: bool FLAGS_enable_quic_delay_forward_security =
false;
On 2014/11/03 18:09:34, Ryan Hamilton wrote:
> I think you can go ahead and set this to true. It shouldn't actually matter
> client-side so it might be worth turning it on to exercise the code path.

Done.