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

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 6d2e400c3efc612da037b6276bcf1c8e34d166ea..407a163c1ac38e8edc53bf0b8d9838a809cd6afa 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -86,10 +86,9 @@ class AckAlarm : public QuicAlarm::Delegate {
  public:
   explicit AckAlarm(QuicConnection* connection) : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
+  void OnAlarm() override {
     DCHECK(connection_->ack_frame_updated());
     connection_->SendAck();
-    return QuicTime::Zero();
   }
 
  private:
@@ -106,10 +105,7 @@ class RetransmissionAlarm : public QuicAlarm::Delegate {
   explicit RetransmissionAlarm(QuicConnection* connection)
       : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
-    connection_->OnRetransmissionTimeout();
-    return QuicTime::Zero();
-  }
+  void OnAlarm() override { connection_->OnRetransmissionTimeout(); }
 
  private:
   QuicConnection* connection_;
@@ -123,11 +119,7 @@ class SendAlarm : public QuicAlarm::Delegate {
  public:
   explicit SendAlarm(QuicConnection* connection) : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
-    connection_->WriteAndBundleAcksIfNotBlocked();
-    // Never reschedule the alarm, since CanWrite does that.
-    return QuicTime::Zero();
-  }
+  void OnAlarm() override { connection_->WriteAndBundleAcksIfNotBlocked(); }
 
  private:
   QuicConnection* connection_;
@@ -139,11 +131,7 @@ class TimeoutAlarm : public QuicAlarm::Delegate {
  public:
   explicit TimeoutAlarm(QuicConnection* connection) : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
-    connection_->CheckForTimeout();
-    // Never reschedule the alarm, since CheckForTimeout does that.
-    return QuicTime::Zero();
-  }
+  void OnAlarm() override { connection_->CheckForTimeout(); }
 
  private:
   QuicConnection* connection_;
@@ -155,10 +143,7 @@ class PingAlarm : public QuicAlarm::Delegate {
  public:
   explicit PingAlarm(QuicConnection* connection) : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
-    connection_->OnPingTimeout();
-    return QuicTime::Zero();
-  }
+  void OnAlarm() override { connection_->OnPingTimeout(); }
 
  private:
   QuicConnection* connection_;
@@ -171,11 +156,7 @@ class MtuDiscoveryAlarm : public QuicAlarm::Delegate {
   explicit MtuDiscoveryAlarm(QuicConnection* connection)
       : connection_(connection) {}
 
-  QuicTime OnAlarm() override {
-    connection_->DiscoverMtu();
-    // DiscoverMtu() handles rescheduling the alarm by itself.
-    return QuicTime::Zero();
-  }
+  void OnAlarm() override { connection_->DiscoverMtu(); }
 
  private:
   QuicConnection* connection_;