Add a QuicConfig option to ask the client not to attempt migration.

Add a QuicConfig option to ask the client not to attempt migration.

Merge internal change: 116712124

R=rch@chromium.org
BUG=

[Ryan Hamilton, 2016-03-16 20:28:54]

rch@chromium.org changed reviewers:
+ jri@chromium.org

[Ryan Hamilton, 2016-03-16 20:28:55]

jri: How should this be wired up so Chrome does the needful?

[Jana, 2016-03-16 21:59:46]

On 2016/03/16 20:28:55, Ryan Hamilton wrote:
> jri: How should this be wired up so Chrome does the needful?

QuicStreamFactory will have to query QuicSession's config_ to figure out if this
option is set and disable migration that way. There's precedence with
non-migratable streams, so basically:
(1) Change
https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_stre...
to if (session->HasNonMigratableStreams() ||
session->config()->DisableConnectionMigration())
(2) Change
https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_stre...
to if (!migrate_sessions_early_ || session->HasNonMigratableStreams() ||
session->config()->DisableConnectionMigration())
(3) You'll need to add tests to quic_stream_factory_test as well... you can
basically simply use the three "NonMigratableStream" tests, with modifications
to set the session's config instead of setting the non-migratable-stream flag.

That should do it, but (1) will overload the current histogram... I can split
this into a new histogram after this CL lands.

You can also land this CL as is, and I can do the rest in a new CL after this
merge, which might be easier.

[Ryan Hamilton, 2016-03-17 00:31:32]

On 2016/03/16 21:59:46, Jana wrote:
> On 2016/03/16 20:28:55, Ryan Hamilton wrote:
> > jri: How should this be wired up so Chrome does the needful?
> 
> QuicStreamFactory will have to query QuicSession's config_ to figure out if
this
> option is set and disable migration that way. There's precedence with
> non-migratable streams, so basically:
> (1) Change
>
https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_stre...
> to if (session->HasNonMigratableStreams() ||
> session->config()->DisableConnectionMigration())
> (2) Change
>
https://code.google.com/p/chromium/codesearch#chromium/src/net/quic/quic_stre...
> to if (!migrate_sessions_early_ || session->HasNonMigratableStreams() ||
> session->config()->DisableConnectionMigration())
> (3) You'll need to add tests to quic_stream_factory_test as well... you can
> basically simply use the three "NonMigratableStream" tests, with modifications
> to set the session's config instead of setting the non-migratable-stream flag.
> 
> That should do it, but (1) will overload the current histogram... I can split
> this into a new histogram after this CL lands.
> 
> You can also land this CL as is, and I can do the rest in a new CL after this
> merge, which might be easier.

If you're planning to do this yourself, that works for me.

LGTM