Remove the (now-empty) sent_info field when logging QUIC ack frames.

net/quic/quic_connection_logger.cc

Index: net/quic/quic_connection_logger.cc
diff --git a/net/quic/quic_connection_logger.cc b/net/quic/quic_connection_logger.cc
index 86f9c6a11737e7cd9e08999109f339ba881fd0f4..6ac4f5563d9462708484a87f8f2a259039d48548 100644
--- a/net/quic/quic_connection_logger.cc
+++ b/net/quic/quic_connection_logger.cc
@@ -102,10 +102,6 @@ base::Value* NetLogQuicStreamFrameCallback(const QuicStreamFrame* frame,
 base::Value* NetLogQuicAckFrameCallback(const QuicAckFrame* frame,
                                         NetLog::LogLevel /* log_level */) {
   base::DictionaryValue* dict = new base::DictionaryValue();
-  base::DictionaryValue* sent_info = new base::DictionaryValue();
-  dict->Set("sent_info", sent_info);
-  sent_info->SetString("least_unacked",
-                       base::Uint64ToString(frame->sent_info.least_unacked));
   base::DictionaryValue* received_info = new base::DictionaryValue();
   dict->Set("received_info", received_info);
   received_info->SetString(