Implement certificate lifetime parameter as required by WebRTC RFC.

webrtc/base/opensslidentity.h

Index: webrtc/base/opensslidentity.h
diff --git a/webrtc/base/opensslidentity.h b/webrtc/base/opensslidentity.h
index c8aa69a76eee5551b6ddd748bc23c0fb2d630c82..dda50be775a635883a4580522cb5a1898222145a 100644
--- a/webrtc/base/opensslidentity.h
+++ b/webrtc/base/opensslidentity.h
@@ -102,7 +102,8 @@ class OpenSSLCertificate : public SSLCertificate {
 class OpenSSLIdentity : public SSLIdentity {
  public:
   static OpenSSLIdentity* Generate(const std::string& common_name,
-                                   const KeyParams& key_params);
+                                   const KeyParams& key_params,
+                                   time_t certificate_lifetime);

[Ryan Sleevi, 2016/03/08 17:04:43]

I would strongly advise against using time_t in a public API, as opposed to a
more clearer expression (base::Time or seconds), due to platform
interoperability w/r/t time_t

[torbjorng (webrtc), 2016/03/30 14:00:29]

Note that Open/BoringSSL uses time_t, and this is an interface to it. We need to
convert someplace from some other type to time_t. (Besides, base::Time is not
available in WebRTC.)

Incidentally, we're working on a new C++ API for these things. It won't be using
time_t, for sure.

[Ryan Sleevi, 2016/03/31 02:07:53]

OpenSSL's API is actually designed around the ASN1_TIME interface. The time_t
bits are part of the legacy interface, and precisely because of issues with
time_t sizing - such as the Y2038 problem. The 'right' thing to use is the
ASN1_TIME interfaces (ASN1_TIME_DIFF, ASN1_GENERALIZEDTIME_set_string,
ASN1_UTCTIME_set_string, etc)

[torbjorng (webrtc), 2016/03/31 13:18:34]

Right, I wasn't aware of that one set of interfaces were considered obsolete. It
is also hard to guess which interfaces are intended as part of the external API.

I created https://bugs.chromium.org/p/webrtc/issues/detail?id=5720 about
cleaning up this.

   static OpenSSLIdentity* GenerateForTest(const SSLIdentityParams& params);
   static SSLIdentity* FromPEMStrings(const std::string& private_key,
                                      const std::string& certificate);