Ability to specify KeyType (RSA, ECDSA) for SSLIdentity generation in libjingle

Note: SSLIdentity::Generate is not able to use KeyType until this CL lands:
https://webrtc-codereview.appspot.com/51189004/


With this CL, the KeyType for SSLIdentity generation can be specified by the PeerConnectionFactory[Interface]::CreatePeerConnection methods, and the KeyType is passed down the layers to where the generation happens.
The KeyType is passed around as follows:
PeerConnectionFactory::CreatePeerConnection -> PeerConnection -> WebRtcSession -> WebRtcSessionDescriptionFactory.

In WebRtcSessionDescriptionFactory the KeyType is passed to a DtlsIdentityStoreInterface::RequestIdentity which calls SSLIdentity::Generate (todo to pass the KeyType to Generate based on torbjorng@'s CL).


This CL also makes big changes to DtlsIdentityStoreInterface and related classes.

- DtlsIdentityStore gets an interface, DtlsIdentityStoreInterface, and the implementation is now called DtlsIdentityStoreImpl.

- DTLSIdentityServiceInterface is removed. This was an unnecessary layer of complexity - DTLSIdentityService simply called the store. The only useful thing was that the interface allowed for a FakeIdentityService used in unittests (for quick precalculated keys).

- Instead, FakeIdentityService becomes FakeDtlsIdentityStoreRSA, implementing DtlsIdentityStoreInterface ("RSA" to clarify that it does not yet support fake-generating other types).

- WebRtcSessionDescriptionFactory is no longer responsible for generating an identity in the event of a DTLS store (or previously DTLS service) not being specified. All generation happens through DtlsIdentityStore[Interface/Impl].

[hbos, 2015-06-05 12:54:42]

hbos@webrtc.org changed reviewers:
+ torbjorng@webrtc.org

[hbos, 2015-06-09 08:20:55]

hbos@webrtc.org changed reviewers:
+ tommi@webrtc.org

[hbos, 2015-06-12 10:18:39]

Patchset #6 (id:100001) has been deleted

[hbos, 2015-06-12 12:46:55]

As noted with comments, improvements can be made to DtlsIdentityStoreImpl, but
please take a first look tommi, it's quite a large CL.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
File talk/app/webrtc/dtlsidentityservice.h (left):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
talk/app/webrtc/dtlsidentityservice.h:41: class DtlsIdentityService : public
webrtc::DTLSIdentityServiceInterface {
Nuked.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
File talk/app/webrtc/dtlsidentitystore.cc (right):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
talk/app/webrtc/dtlsidentitystore.cc:76: // to generate one.
In the old code, |free_identity_| was checked when RequestIdentity was called
and if we had none then we generated a new one. This has the flaw that if we are
currently generating an identity for |free_identity_|, but we have not finished
yet, the old code would  signal to "unnecessarily" generate another identity.

This seemed like a problem to me and I added store_->ReleaseFreeRSAIdentity here
to abort generating another one, but at the cost of having to use a lock around
|free_(rsa_)identity_|.

As I'm writing this though I realized that generating an extra identity
"unnecessarily" would not have been a practical problem, since we'd want to
queue a preemptive RSA generation in the background as soon as |free_identity_|
was released anyway. The end result being the same as long as |worker_thread_|
!= |signaling_thread_|.

I'm sure you'll object to me adding this lock so we can discuss me changing this
up a bit.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
talk/app/webrtc/dtlsidentitystore.cc:199: // Enqueue the request.
I made it simple by always queuing a request and handling them the same way.
However, ECDA being cheap we could generate those on the signaling thread and
avoid a couple of context switches. (Would still have to do Post though so that
the result is returned async.)

We could also avoid a couple of context switches by checking if we have a
|free_rsa_identity_| already here like the old code.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
File talk/app/webrtc/dtlsidentitystore.h (right):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
talk/app/webrtc/dtlsidentitystore.h:47: class DtlsIdentityRequestObserver :
public rtc::RefCountInterface {
Moved from peerconnetctionfactory.h (and renamed DTLS -> Dtls).

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/dtlsiden...
talk/app/webrtc/dtlsidentitystore.h:142: std::list<IdentityRequest>
pending_requests_;
(Used like a queue, list instead of queue to be able to iterate.)

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/peerconn...
File talk/app/webrtc/peerconnection.h (left):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/peerconn...
talk/app/webrtc/peerconnection.h:164: PeerConnectionObserver* observer);
Declared, not defined. Removing.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/peerconn...
File talk/app/webrtc/peerconnectioninterface.h (left):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/peerconn...
talk/app/webrtc/peerconnectioninterface.h:462: class DTLSIdentityRequestObserver
: public rtc::RefCountInterface {
Moved to dtlsidentitystore.h (and renamed DTLS -> Dtls)

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/peerconn...
talk/app/webrtc/peerconnectioninterface.h:477: class
DTLSIdentityServiceInterface {
Nuked.

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/proxy.h
File talk/app/webrtc/proxy.h (right):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/proxy.h#...
talk/app/webrtc/proxy.h:88: }
Needed a 6th parameter...

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/test/fak...
File talk/app/webrtc/test/fakedtlsidentityservice.h (left):

https://codereview.webrtc.org/1151943005/diff/120001/talk/app/webrtc/test/fak...
talk/app/webrtc/test/fakedtlsidentityservice.h:67: public rtc::MessageHandler {
This file has been renamed to fakedtlsidentitystore.h.

This is renamed to FakeDtlsIdentityStore which extends the
DtlsIdentityStoreInterface instead of service, but does the same thing.

https://codereview.webrtc.org/1151943005/diff/120001/webrtc/base/sslidentity.h
File webrtc/base/sslidentity.h (right):

https://codereview.webrtc.org/1151943005/diff/120001/webrtc/base/sslidentity....
webrtc/base/sslidentity.h:28: enum KeyType {
(Also defined in torbjorng@'s CL, to be merged.)

[hbos, 2015-06-15 12:39:55]

This CL has been split up into:
https://codereview.webrtc.org/1176383004/
https://codereview.webrtc.org/1186083002/