Update from chromium https://crrev.com/301725/

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 2571868a513c4916200ea619e4b057a03d707d1d..9e01fd4bfb00d99d7585636bd193b7d4a9deb60d 100644
--- a/net/tools/quic/test_tools/packet_dropping_test_writer.cc
+++ b/net/tools/quic/test_tools/packet_dropping_test_writer.cc
@@ -21,7 +21,7 @@ class WriteUnblockedAlarm : public QuicAlarm::Delegate {
   explicit WriteUnblockedAlarm(PacketDroppingTestWriter* writer)
       : writer_(writer) {}
 
-  virtual QuicTime OnAlarm() override {
+  QuicTime OnAlarm() override {
     DVLOG(1) << "Unblocking socket.";
     writer_->OnCanWrite();
     return QuicTime::Zero();
@@ -37,9 +37,7 @@ class DelayAlarm : public QuicAlarm::Delegate {
  public:
   explicit DelayAlarm(PacketDroppingTestWriter* writer) : writer_(writer) {}
 
-  virtual QuicTime OnAlarm() override {
-    return writer_->ReleaseOldPackets();
-  }
+  QuicTime OnAlarm() override { return writer_->ReleaseOldPackets(); }
 
  private:
   PacketDroppingTestWriter* writer_;