Remove unused histograms for QUIC

net/quic/chromium/quic_connection_logger.cc

Index: net/quic/chromium/quic_connection_logger.cc
diff --git a/net/quic/chromium/quic_connection_logger.cc b/net/quic/chromium/quic_connection_logger.cc
index df5c499b5b812c37b72fc3d8f39a4021d728d63f..bd09e828abf8f12e2601c3e81c8406d2259ee2a2 100644
--- a/net/quic/chromium/quic_connection_logger.cc
+++ b/net/quic/chromium/quic_connection_logger.cc
@@ -792,8 +792,6 @@ void QuicConnectionLogger::RecordLossHistograms() const {
 
   base::HistogramBase* is_not_ack_histogram =
       GetPacketNumberHistogram("IsNotAck_");
-  base::HistogramBase* is_an_ack_histogram =
-      GetPacketNumberHistogram("IsAnAck_");
   base::HistogramBase* packet_arrived_histogram =
       GetPacketNumberHistogram("Ack_");
   base::HistogramBase* packet_missing_histogram =
@@ -817,9 +815,7 @@ void QuicConnectionLogger::RecordLossHistograms() const {
   // Zero is an invalid packet sequence number.
   DCHECK(!received_packets_[0]);
   for (size_t i = 1; i <= last_index; ++i) {
-    if (received_acks_[i])
-      is_an_ack_histogram->Add(i);
-    else
+    if (!received_acks_[i])
       is_not_ack_histogram->Add(i);
 
     packet_pattern_21 >>= 1;