Fix a QUIC bug in which PING frames were not being ACK'd.

net/quic/quic_connection_test.cc

Index: net/quic/quic_connection_test.cc
diff --git a/net/quic/quic_connection_test.cc b/net/quic/quic_connection_test.cc
index 5befba789063c8ffd551fe2a6115df1dea2f16ed..c137db9c3c177afcccbbd218f9be83e401ba95e4 100644
--- a/net/quic/quic_connection_test.cc
+++ b/net/quic/quic_connection_test.cc
@@ -733,6 +733,13 @@ class QuicConnectionTest : public ::testing::TestWithParam<QuicVersion> {
     return encrypted->length();
   }
 
+  void ProcessPingPacket(QuicPacketSequenceNumber number) {
+    scoped_ptr<QuicPacket> packet(ConstructPingPacket(number));
+    scoped_ptr<QuicEncryptedPacket> encrypted(framer_.EncryptPacket(
+        ENCRYPTION_NONE, number, *packet));
+    connection_.ProcessUdpPacket(IPEndPoint(), IPEndPoint(), *encrypted);
+  }
+
   void ProcessClosePacket(QuicPacketSequenceNumber number,
                           QuicFecGroupNumber fec_group) {
     scoped_ptr<QuicPacket> packet(ConstructClosePacket(number, fec_group));
@@ -872,6 +879,27 @@ class QuicConnectionTest : public ::testing::TestWithParam<QuicVersion> {
     return packet;
   }
 
+  QuicPacket* ConstructPingPacket(QuicPacketSequenceNumber number) {
+    header_.public_header.connection_id = connection_id_;
+    header_.packet_sequence_number = number;
+    header_.public_header.reset_flag = false;
+    header_.public_header.version_flag = false;
+    header_.entropy_flag = false;
+    header_.fec_flag = false;
+    header_.is_in_fec_group = NOT_IN_FEC_GROUP;
+    header_.fec_group = 0;
+
+    QuicPingFrame ping;
+
+    QuicFrames frames;
+    QuicFrame frame(&ping);
+    frames.push_back(frame);
+    QuicPacket* packet =
+        BuildUnsizedDataPacket(&framer_, header_, frames).packet;
+    EXPECT_TRUE(packet != NULL);
+    return packet;
+  }
+
   QuicPacket* ConstructClosePacket(QuicPacketSequenceNumber number,
                                    QuicFecGroupNumber fec_group) {
     header_.public_header.connection_id = connection_id_;
@@ -2967,6 +2995,16 @@ TEST_P(QuicConnectionTest, SendDelayedAckOnSecondPacket) {
   EXPECT_FALSE(connection_.GetAckAlarm()->IsSet());
 }
 
+TEST_P(QuicConnectionTest, SendDelayedAckForPing) {
+  if (version() < QUIC_VERSION_18) {
+    return;
+  }
+  EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
+  EXPECT_FALSE(connection_.GetAckAlarm()->IsSet());
+  ProcessPingPacket(1);
+  EXPECT_TRUE(connection_.GetAckAlarm()->IsSet());
+}
+
 TEST_P(QuicConnectionTest, NoAckOnOldNacks) {
   EXPECT_CALL(visitor_, OnSuccessfulVersionNegotiation(_));
   // Drop one packet, triggering a sequence of acks.