Add GoEphemeralKeySource to improve CPS.

  * Connection throughput increased to 3800 CPS from 2800 CPS (+30%)

src/adaptor.cc

@@ -6,6 +6,7 @@
 #include "go_quic_spdy_server_stream_go_wrapper.h"
 #include "go_quic_alarm_go_wrapper.h"
 #include "go_proof_source.h"
+#include "go_ephemeral_key_source.h"
 
 #include "net/quic/quic_connection.h"
 #include "net/quic/quic_clock.h"
@@ -53,6 +54,8 @@ GoQuicDispatcher *create_quic_dispatcher(void* go_udp_conn, void* go_quic_dispat
   QuicCryptoServerConfig* crypto_config = new QuicCryptoServerConfig("secret", QuicRandom::GetInstance());
   QuicClock* clock = new QuicClock(); // Deleted by scoped ptr of TestConnectionHelper
   QuicRandom* random_generator = QuicRandom::GetInstance();
+  net::EphemeralKeySource *keySource = new GoEphemeralKeySource();
+  crypto_config->SetEphemeralKeySource(keySource);
 
   TestConnectionHelper *helper = new TestConnectionHelper(go_task_runner, clock, random_generator); // Deleted by delete_go_quic_dispatcher()
   QuicVersionVector versions(net::QuicSupportedVersions());

src/go_ephemeral_key_source.cc

@@ -0,0 +1,25 @@
+#include "go_ephemeral_key_source.h"
+
+GoEphemeralKeySource::GoEphemeralKeySource() : forward_secure_key_exchange_(nullptr), key_created_time_(net::QuicTime::Zero()) {
+}
+
+std::string GoEphemeralKeySource::CalculateForwardSecureKey(
+      const net::KeyExchange* key_exchange,
+      net::QuicRandom* rand,
+      net::QuicTime now,
+      base::StringPiece peer_public_value,
+      std::string* public_value) {
+  // Cache forward_secure_key_exchange for 10 seconds
+  if (forward_secure_key_exchange_.get() == nullptr ||
+          now.Subtract(key_created_time_).ToSeconds() > 10) {
+    forward_secure_key_exchange_.reset(key_exchange->NewKeyPair(rand));
+    key_created_time_ = now;
+  }
+
+  *public_value =
+      forward_secure_key_exchange_->public_value().as_string();
+  std::string forward_secure_premaster_secret;
+  forward_secure_key_exchange_->CalculateSharedKey(
+      peer_public_value, &forward_secure_premaster_secret);
+  return forward_secure_premaster_secret;
+}

src/go_ephemeral_key_source.h

@@ -0,0 +1,25 @@
+#ifndef __GO_EPHEMERAL_KEY_SOURCE__H__
+#define __GO_EPHEMERAL_KEY_SOURCE__H__
+
+#include "net/quic/crypto/key_exchange.h"
+#include "net/quic/crypto/ephemeral_key_source.h"
+#include "net/quic/quic_time.h"
+#include "base/memory/scoped_ptr.h"
+
+class GoEphemeralKeySource : public net::EphemeralKeySource {
+ public:
+  GoEphemeralKeySource();
+
+  virtual std::string CalculateForwardSecureKey(
+      const net::KeyExchange* key_exchange,
+      net::QuicRandom* rand,
+      net::QuicTime now,
+      base::StringPiece peer_public_value,
+      std::string* public_value) override;
+
+ private:
+  scoped_ptr<net::KeyExchange> forward_secure_key_exchange_;
+  net::QuicTime key_created_time_;
+};
+
+#endif  // __GO_EPHEMERAL_KEY_SOURCE__H__