Land Recent QUIC Changes.

net/quic/quic_alarm.cc

 // 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.
 
 #include "net/quic/quic_alarm.h"
 
 #include "base/logging.h"
 
 namespace net {
 
 QuicAlarm::QuicAlarm(Delegate* delegate)
     : delegate_(delegate),
       deadline_(QuicTime::Zero()) {
 }
 
 QuicAlarm::~QuicAlarm() {}
 
 void QuicAlarm::Set(QuicTime deadline) {
   DCHECK(!IsSet());
   DCHECK(deadline.IsInitialized());
   deadline_ = deadline;
   SetImpl();
 }
 
 void QuicAlarm::Cancel() {
   deadline_ = QuicTime::Zero();
   CancelImpl();
 }
 
+void QuicAlarm::Update(QuicTime deadline, QuicTime::Delta granularity) {
+  if (!deadline.IsInitialized()) {
+    Cancel();
+    return;
+  }
+  if (std::abs(deadline.Subtract(deadline_).ToMicroseconds()) <
+          granularity.ToMicroseconds()) {
+    return;
+  }
+  Cancel();
+  Set(deadline);
+}
+
 bool QuicAlarm::IsSet() const {
   return deadline_.IsInitialized();
 }
 
 void QuicAlarm::Fire() {
   if (!deadline_.IsInitialized()) {
     return;
   }
 
   deadline_ = QuicTime::Zero();
   QuicTime deadline = delegate_->OnAlarm();
   // delegate_->OnAlarm() might call Set(), in which case  deadline_ will
   // already contain the new value, so don't overwrite it.
   if (!deadline_.IsInitialized() && deadline.IsInitialized()) {
     Set(deadline);
   }
 }
 
 }  // namespace net