Deprecate FLAGS_quic_only_track_sent_packets.

net/quic/core/quic_connection.cc

Index: net/quic/core/quic_connection.cc
diff --git a/net/quic/core/quic_connection.cc b/net/quic/core/quic_connection.cc
index fdb17f8339d6d833c6cc7074d78b5f7d4c849f83..aba5db4d3e40dc77925cc1c8800710776ff8d8a5 100644
--- a/net/quic/core/quic_connection.cc
+++ b/net/quic/core/quic_connection.cc
@@ -1699,30 +1699,27 @@ bool QuicConnection::WritePacket(SerializedPacket* packet) {
     }
   }
 
-  if (FLAGS_quic_only_track_sent_packets) {
-    // In some cases, an MTU probe can cause EMSGSIZE. This indicates that the
-    // MTU discovery is permanently unsuccessful.
-    if (result.status == WRITE_STATUS_ERROR &&
-        result.error_code == kMessageTooBigErrorCode &&
-        packet->retransmittable_frames.empty() &&
-        packet->encrypted_length > long_term_mtu_) {
-      mtu_discovery_target_ = 0;
-      mtu_discovery_alarm_->Cancel();
-      // The write failed, but the writer is not blocked, so return true.
-      return true;
-    }
+  // In some cases, an MTU probe can cause EMSGSIZE. This indicates that the
+  // MTU discovery is permanently unsuccessful.
+  if (result.status == WRITE_STATUS_ERROR &&
+      result.error_code == kMessageTooBigErrorCode &&
+      packet->retransmittable_frames.empty() &&
+      packet->encrypted_length > long_term_mtu_) {
+    mtu_discovery_target_ = 0;
+    mtu_discovery_alarm_->Cancel();
+    // The write failed, but the writer is not blocked, so return true.
+    return true;
+  }
 
-    if (result.status == WRITE_STATUS_ERROR) {
-      OnWriteError(result.error_code);
-      DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
-                  << " from host "
-                  << (self_address().address().empty()
-                          ? " empty address "
-                          : self_address().ToStringWithoutPort())
-                  << " to address " << peer_address().ToString()
-                  << " with error code " << result.error_code;
-      return false;
-    }
+  if (result.status == WRITE_STATUS_ERROR) {
+    OnWriteError(result.error_code);
+    DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
+                << " from host " << (self_address().address().empty()
+                                         ? " empty address "
+                                         : self_address().ToStringWithoutPort())
+                << " to address " << peer_address().ToString()
+                << " with error code " << result.error_code;
+    return false;
   }
 
   if (result.status != WRITE_STATUS_ERROR && debug_visitor_ != nullptr) {
@@ -1768,31 +1765,6 @@ bool QuicConnection::WritePacket(SerializedPacket* packet) {
     ++stats_.packets_retransmitted;
   }
 
-  if (!FLAGS_quic_only_track_sent_packets) {
-    // In some cases, an MTU probe can cause EMSGSIZE. This indicates that the
-    // MTU discovery is permanently unsuccessful.
-    if (result.status == WRITE_STATUS_ERROR &&
-        result.error_code == kMessageTooBigErrorCode &&
-        packet->retransmittable_frames.empty() &&
-        packet->encrypted_length > long_term_mtu_) {
-      mtu_discovery_target_ = 0;
-      mtu_discovery_alarm_->Cancel();
-      return true;
-    }
-
-    if (result.status == WRITE_STATUS_ERROR) {
-      OnWriteError(result.error_code);
-      DLOG(ERROR) << ENDPOINT << "failed writing " << encrypted_length
-                  << " from host "
-                  << (self_address().address().empty()
-                          ? " empty address "
-                          : self_address().ToStringWithoutPort())
-                  << " to address " << peer_address().ToString()
-                  << " with error code " << result.error_code;
-      return false;
-    }
-  }
-
   return true;
 }