relnote: Use NotifyChangedPriority when updating alarms instead of canceling and reregistering. Gua…

net/quic/quic_alarm.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_QUIC_ALARM_H_
 #define NET_QUIC_QUIC_ALARM_H_
 
 #include <memory>
 
 #include "base/macros.h"
@@ skipping 45 matching lines @@
  protected:
   // Subclasses implement this method to perform the platform-specific
   // scheduling of the alarm.  Is called from Set() or Fire(), after the
   // deadline has been updated.
   virtual void SetImpl() = 0;
 
   // Subclasses implement this method to perform the platform-specific
   // cancelation of the alarm.
   virtual void CancelImpl() = 0;
 
+  // Subclasses implement this method to perform the platform-specific update of
+  // the alarm if there exists a more optimal implementation than calling
+  // CancelImpl() and SetImpl().
+  virtual void UpdateImpl();
+
   // Called by subclasses when the alarm fires.  Invokes the
   // delegates |OnAlarm| if a delegate is set, and if the deadline
   // has been exceeded.  Implementations which do not remove the
   // alarm from the underlying scheduler on Cancel() may need to handle
   // the situation where the task executes before the deadline has been
   // reached, in which case they need to reschedule the task and must not
   // call invoke this method.
   void Fire();
 
  private:
   QuicArenaScopedPtr<Delegate> delegate_;
   QuicTime deadline_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicAlarm);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_ALARM_H_