Add an Update method on QuicAlarm which contains a granularity. Also

net/quic/quic_alarm_test.cc

Index: net/quic/quic_alarm_test.cc
diff --git a/net/quic/quic_alarm_test.cc b/net/quic/quic_alarm_test.cc
index cc5028b8457f04517324c4b5f4310110a9a1b603..434bb38fe06d3faf9b5b6971dfe45fd5181de043 100644
--- a/net/quic/quic_alarm_test.cc
+++ b/net/quic/quic_alarm_test.cc
@@ -88,6 +88,25 @@ TEST_F(QuicAlarmTest, Cancel) {
   EXPECT_EQ(QuicTime::Zero(), alarm_.deadline());
 }
 
+TEST_F(QuicAlarmTest, Update) {
+  QuicTime deadline = QuicTime::Zero().Add(QuicTime::Delta::FromSeconds(7));
+  alarm_.Set(deadline);
+  QuicTime new_deadline = QuicTime::Zero().Add(QuicTime::Delta::FromSeconds(8));
+  alarm_.Update(new_deadline, QuicTime::Delta::Zero());
+  EXPECT_TRUE(alarm_.IsSet());
+  EXPECT_TRUE(alarm_.scheduled());
+  EXPECT_EQ(new_deadline, alarm_.deadline());
+}
+
+TEST_F(QuicAlarmTest, UpdateWithZero) {
+  QuicTime deadline = QuicTime::Zero().Add(QuicTime::Delta::FromSeconds(7));
+  alarm_.Set(deadline);
+  alarm_.Update(QuicTime::Zero(), QuicTime::Delta::Zero());
+  EXPECT_FALSE(alarm_.IsSet());
+  EXPECT_FALSE(alarm_.scheduled());
+  EXPECT_EQ(QuicTime::Zero(), alarm_.deadline());
+}
+
 TEST_F(QuicAlarmTest, Fire) {
   QuicTime deadline = QuicTime::Zero().Add(QuicTime::Delta::FromSeconds(7));
   alarm_.Set(deadline);