Clear the QUIC cached proof when a client receives a REJ w/o a PROF tag.

net/quic/crypto/crypto_handshake.cc

Index: net/quic/crypto/crypto_handshake.cc
diff --git a/net/quic/crypto/crypto_handshake.cc b/net/quic/crypto/crypto_handshake.cc
index d6a76f9f51195005e52a385a06cfbb636265f153..ce854c82e840fe539f4ed67061a3b38985eacfff 100644
--- a/net/quic/crypto/crypto_handshake.cc
+++ b/net/quic/crypto/crypto_handshake.cc
@@ -470,6 +470,12 @@ void QuicCryptoClientConfig::CachedState::SetProof(const vector<string>& certs,
   server_config_sig_ = signature.as_string();
 }
 
+void QuicCryptoClientConfig::CachedState::ClearProof() {
+  SetProofInvalid();
+  certs_.clear();
+  server_config_sig_.clear();
+}
+
 void QuicCryptoClientConfig::CachedState::SetProofValid() {
   server_config_valid_ = true;
 }
@@ -832,6 +838,8 @@ QuicErrorCode QuicCryptoClientConfig::ProcessRejection(
     }
 
     cached->SetProof(certs, proof);
+  } else {
+    cached->ClearProof();
   }
 
   return QUIC_NO_ERROR;