Support generation of EC keys using P256 curve and support ECDSA certs.

webrtc/base/sslidentity.h

Index: webrtc/base/sslidentity.h
diff --git a/webrtc/base/sslidentity.h b/webrtc/base/sslidentity.h
index 59f87d07d217cce38eb3b88b62ec4d9518a7173a..15e23a357b2c68d2f974cc6dcc7c54e7460c5ede 100644
--- a/webrtc/base/sslidentity.h
+++ b/webrtc/base/sslidentity.h
@@ -117,6 +117,7 @@ struct SSLIdentityParams {
   std::string common_name;
   int not_before;  // in seconds.
   int not_after;  // in seconds.
+  KeyType key_type;
 };
 
 // Our identity in an SSL negotiation: a keypair and certificate (both
@@ -129,7 +130,8 @@ class SSLIdentity {
   // subject and issuer name, otherwise a random string will be used.
   // Returns NULL on failure.
   // Caller is responsible for freeing the returned object.
-  static SSLIdentity* Generate(const std::string& common_name);
+  static SSLIdentity* Generate(const std::string& common_name,
+                               KeyType key_type);
 
   // Generates an identity with the specified validity period.
   static SSLIdentity* GenerateForTest(const SSLIdentityParams& params);
@@ -159,6 +161,7 @@ class SSLIdentity {
 
 extern const char kPemTypeCertificate[];
 extern const char kPemTypeRsaPrivateKey[];
+extern const char kPemTypeEcPrivateKey[];
 
 }  // namespace rtc