Change name of TLS handshaker's delegate_ member to handshaker_delegate_.

TLS server handshaker is a subclass of QuicStream. QuicStream has a another delegate member called session_delegate. This change is to make it clear on which delegate is called for each piece of code.

gfe-relnote: name change only. Not protected.
PiperOrigin-RevId: 294791081
Change-Id: I22ee62753d21e4052822254cb9715dfde0cff72f
diff --git a/quic/core/tls_client_handshaker.cc b/quic/core/tls_client_handshaker.cc
index ece7a05..350a9ae 100644
--- a/quic/core/tls_client_handshaker.cc
+++ b/quic/core/tls_client_handshaker.cc
@@ -286,8 +286,8 @@
     return;
   }
   handshake_confirmed_ = true;
-  delegate()->DiscardOldEncryptionKey(ENCRYPTION_HANDSHAKE);
-  delegate()->DiscardOldDecryptionKey(ENCRYPTION_HANDSHAKE);
+  handshaker_delegate()->DiscardOldEncryptionKey(ENCRYPTION_HANDSHAKE);
+  handshaker_delegate()->DiscardOldDecryptionKey(ENCRYPTION_HANDSHAKE);
 }
 
 void TlsClientHandshaker::AdvanceHandshake() {
@@ -394,7 +394,7 @@
   crypto_negotiated_params_->peer_signature_algorithm =
       SSL_get_peer_signature_algorithm(ssl());
 
-  delegate()->SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
+  handshaker_delegate()->SetDefaultEncryptionLevel(ENCRYPTION_FORWARD_SECURE);
 }
 
 enum ssl_verify_result_t TlsClientHandshaker::VerifyCert(uint8_t* out_alert) {
@@ -465,8 +465,8 @@
   if (level == ENCRYPTION_HANDSHAKE &&
       state_ < STATE_ENCRYPTION_HANDSHAKE_DATA_SENT) {
     state_ = STATE_ENCRYPTION_HANDSHAKE_DATA_SENT;
-    delegate()->DiscardOldEncryptionKey(ENCRYPTION_INITIAL);
-    delegate()->DiscardOldDecryptionKey(ENCRYPTION_INITIAL);
+    handshaker_delegate()->DiscardOldEncryptionKey(ENCRYPTION_INITIAL);
+    handshaker_delegate()->DiscardOldDecryptionKey(ENCRYPTION_INITIAL);
   }
   TlsHandshaker::WriteMessage(level, data);
 }