gfe-relnote: change logs about window update frames from DLOG(INFO) to DVLOG(1).

When using MESSAGE frames in WebRTC, we never send any retransmittable packets.
QUIC sends a window update frame every few packets to provide a retransmittable
frame, from here:
http://google3/third_party/quic/core/quic_session.cc?l=1468&rcl=264213918

That results in log spam from received window updates on the other endpoint.

PiperOrigin-RevId: 264681195
Change-Id: Ib4d62b4acb1b6dfb9d9e96994df2b4712f3b33e2
diff --git a/quic/core/quic_connection.cc b/quic/core/quic_connection.cc
index e78b0d0..c5020fe 100644
--- a/quic/core/quic_connection.cc
+++ b/quic/core/quic_connection.cc
@@ -1232,9 +1232,9 @@
   if (debug_visitor_ != nullptr) {
     debug_visitor_->OnWindowUpdateFrame(frame, time_of_last_received_packet_);
   }
-  QUIC_DLOG(INFO) << ENDPOINT << "WINDOW_UPDATE_FRAME received for stream: "
-                  << frame.stream_id
-                  << " with byte offset: " << frame.byte_offset;
+  QUIC_DVLOG(1) << ENDPOINT << "WINDOW_UPDATE_FRAME received for stream: "
+                << frame.stream_id
+                << " with byte offset: " << frame.byte_offset;
   visitor_->OnWindowUpdateFrame(frame);
   should_last_packet_instigate_acks_ = true;
   return connected_;
diff --git a/quic/core/quic_session.cc b/quic/core/quic_session.cc
index a335804..15fcf24 100644
--- a/quic/core/quic_session.cc
+++ b/quic/core/quic_session.cc
@@ -474,10 +474,10 @@
       QuicUtils::GetInvalidStreamId(connection_->transport_version())) {
     // This is a window update that applies to the connection, rather than an
     // individual stream.
-    QUIC_DLOG(INFO) << ENDPOINT
-                    << "Received connection level flow control window "
-                       "update with byte offset: "
-                    << frame.byte_offset;
+    QUIC_DVLOG(1) << ENDPOINT
+                  << "Received connection level flow control window "
+                     "update with byte offset: "
+                  << frame.byte_offset;
     flow_controller_.UpdateSendWindowOffset(frame.byte_offset);
     return;
   }