Bugzilla

Currently, we're calculating feedback_rtt in GoogCcNetworkController::OnTransportPacketsFeedback:
```
    TimeDelta feedback_rtt =
        report.feedback_time - feedback.sent_packet.send_time;
```
This number can be negative (and probably shouldn't be allowed).  A negative number causes and assert in GoogCcNetworkController::UpdateCongestionWindowSize here:
```
  DataSize data_window = last_loss_based_target_rate_ * time_window;
```

Currently, we're calculating feedback_rtt in GoogCcNetworkController::OnTransportPacketsFeedback:
```
    TimeDelta feedback_rtt =
        report.feedback_time - feedback.sent_packet.send_time;
```
This number can be negative (and probably shouldn't be allowed).  A negative number causes and assert in GoogCcNetworkController::UpdateCongestionWindowSize here:
```
  DataSize data_window = last_loss_based_target_rate_ * time_window;
```
We currently don't call ```UpdateCongestionWindowSize``` because we have no ```QueueSize``` set in the field trial string.  Prior to the fast-forward work, there was no default congestion window trial string, so we also never called ```UpdateCongestionWindowSize```.

Currently, we're calculating feedback_rtt in GoogCcNetworkController::OnTransportPacketsFeedback:
```
    TimeDelta feedback_rtt =
        report.feedback_time - feedback.sent_packet.send_time;
```
This number can be negative (and probably shouldn't be allowed).  A negative number causes an assert in GoogCcNetworkController::UpdateCongestionWindowSize here:
```
  DataSize data_window = last_loss_based_target_rate_ * time_window;
```
We currently don't call ```UpdateCongestionWindowSize``` because we have no ```QueueSize``` set in the field trial string.  Prior to the fast-forward work, there was no default congestion window trial string, so we also never called ```UpdateCongestionWindowSize```.