Add client certificates to HttpsServer and HttpClient.

Add client certificates to HttpsServer and HttpClient.

BUG=

Committed: https://code.google.com/p/dart/source/detail?r=16097

[Bill Hesse, 2012-12-12 14:00:58]

https://codereview.chromium.org/11553027/diff/3001/tests/standalone/io/https_...
File tests/standalone/io/https_client_certificate_test.dart (right):

https://codereview.chromium.org/11553027/diff/3001/tests/standalone/io/https_...
tests/standalone/io/https_client_certificate_test.dart:90:
test().chain(test).then((_) {
Indentation is fixed.

[Søren Gjesse, 2012-12-12 15:27:07]

lgtm.

I think we should consider the callback solution, but for now this is OK.

https://codereview.chromium.org/11553027/diff/3001/sdk/lib/io/http.dart
File sdk/lib/io/http.dart (right):

https://codereview.chromium.org/11553027/diff/3001/sdk/lib/io/http.dart#newco...
sdk/lib/io/http.dart:832: /**
As discussed offline this makes the client certificate configuration global to
the HttpClient. This is probably OK, as adding optional certificate parameters
for all methods opening a connection would be a pain.

Another option would be to have a callback which is called when the server
requests a certificate. This callback would then be called the first time a
specific server requesting a certificate was contacted. After that this
certificate information would be cached.

https://codereview.chromium.org/11553027/diff/3001/tests/standalone/io/https_...
File tests/standalone/io/https_client_certificate_test.dart (right):

https://codereview.chromium.org/11553027/diff/3001/tests/standalone/io/https_...
tests/standalone/io/https_client_certificate_test.dart:72: // Run second test
with a certificate name.
How about moving this setting of the certificate name into the code in main? It
seems a bit subtle to have that here.