Downgrade entering/leaving batch mode log messages to DVLOG(2).

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index c5290627776318ae666da1feaef253a66fc17f5a..43a6ff30bea8e17721054747e7d62b1933ff5844 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -2266,7 +2266,7 @@ QuicConnection::ScopedPacketBundler::ScopedPacketBundler(
   // Move generator into batch mode. If caller wants us to include an ack,
   // check the delayed-ack timer to see if there's ack info to be sent.
   if (!already_in_batch_mode_) {
-    DVLOG(1) << "Entering Batch Mode.";
+    DVLOG(2) << "Entering Batch Mode.";
     connection_->packet_generator_.StartBatchOperations();
   }
   if (ShouldSendAck(ack_mode)) {
@@ -2299,7 +2299,7 @@ QuicConnection::ScopedPacketBundler::~ScopedPacketBundler() {
   }
   // If we changed the generator's batch state, restore original batch state.
   if (!already_in_batch_mode_) {
-    DVLOG(1) << "Leaving Batch Mode.";
+    DVLOG(2) << "Leaving Batch Mode.";
     connection_->packet_generator_.FinishBatchOperations();
   }
   DCHECK_EQ(already_in_batch_mode_,