Remove unused return value from QuicAlarm::Delegate::OnAlarm. No behavior change, not protected.

net/quic/quic_alarm.cc

Index: net/quic/quic_alarm.cc
diff --git a/net/quic/quic_alarm.cc b/net/quic/quic_alarm.cc
index 371cbe98d7f32aa356c741e64939e675e41ee20e..ca407b52d914dd9a8adee1d023cccd6cf0596ad9 100644
--- a/net/quic/quic_alarm.cc
+++ b/net/quic/quic_alarm.cc
@@ -53,14 +53,7 @@ void QuicAlarm::Fire() {
   }
 
   deadline_ = QuicTime::Zero();
-  QuicTime new_deadline = delegate_->OnAlarm();
-  // delegate_->OnAlarm() might call Set(), in which case deadline_
-  // will already contain the new value, so don't overwrite it.  Also,
-  // OnAlarm() might delete |this| so check |deadline| before
-  // |deadline_|.
-  if (new_deadline.IsInitialized() && !IsSet()) {
-    Set(new_deadline);
-  }
+  delegate_->OnAlarm();
 }
 
 }  // namespace net