Backport r12229 from the trunk....

Backport r12229 from the trunk.
Original review URL: http://codereview.chromium.org/42380

Implement SSL renegotiation.

In the Windows Schannel API, a server requests renegotiation
when DecryptMessage (decrypting received data) returns
SEC_I_RENEGOTIATE.  We need to jump to the handshake
sequence, and when handshake completes, come back to reading
data.

I also cleaned up the code.  I created the
SetNextStateForRead and FreeSendBuffer functions to share
common code, and made sure our handshake sequence is
completely equivalent to the handshake sequence in the
Platform SDK WebClient.c sample.

R=mal
BUG=6893
TEST=Visit these sites, which request SSL renegotiation:
https://secure.skandiabanken.se/Skbsecure/LoginInternet/SKBLoginInternet.aspx
https://secure.skandiabanken.no/SkbSecure/Authentication/Otp/Default.ashx
https://www.myopenid.com/signin_certificate

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=12430

[wtc, 2009-03-23 20:32:11]

Mark,

I'd like to backport the SSL renegotiation code to the
169 branch for the Beta channel.  This is a regression
in the new HTTP stack, compared with 1.0.

Please approve this backport for 2.0 Beta.  Thanks.