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

net/tools/quic/test_tools/packet_dropping_test_writer.cc

Index: net/tools/quic/test_tools/packet_dropping_test_writer.cc
diff --git a/net/tools/quic/test_tools/packet_dropping_test_writer.cc b/net/tools/quic/test_tools/packet_dropping_test_writer.cc
index ed46a071dcafee4173e446dfc120fc226ce9b9be..3858b7828b82504d7a38f99d2bceaa595dcad437 100644
--- a/net/tools/quic/test_tools/packet_dropping_test_writer.cc
+++ b/net/tools/quic/test_tools/packet_dropping_test_writer.cc
@@ -20,10 +20,9 @@ class WriteUnblockedAlarm : public QuicAlarm::Delegate {
   explicit WriteUnblockedAlarm(PacketDroppingTestWriter* writer)
       : writer_(writer) {}
 
-  QuicTime OnAlarm() override {
+  void OnAlarm() override {
     DVLOG(1) << "Unblocking socket.";
     writer_->OnCanWrite();
-    return QuicTime::Zero();
   }
 
  private:
@@ -36,7 +35,12 @@ class DelayAlarm : public QuicAlarm::Delegate {
  public:
   explicit DelayAlarm(PacketDroppingTestWriter* writer) : writer_(writer) {}
 
-  QuicTime OnAlarm() override { return writer_->ReleaseOldPackets(); }
+  void OnAlarm() override {
+    QuicTime new_deadline = writer_->ReleaseOldPackets();
+    if (new_deadline.IsInitialized()) {
+      writer_->SetDelayAlarm(new_deadline);
+    }
+  }
 
  private:
   PacketDroppingTestWriter* writer_;
@@ -203,6 +207,10 @@ QuicTime PacketDroppingTestWriter::ReleaseOldPackets() {
   return QuicTime::Zero();
 }
 
+void PacketDroppingTestWriter::SetDelayAlarm(QuicTime new_deadline) {
+  delay_alarm_->Set(new_deadline);
+}
+
 void PacketDroppingTestWriter::OnCanWrite() {
   on_can_write_->OnCanWrite();
 }