Add a new finch experiment to control the system buffer size.

content/browser/renderer_host/p2p/socket_host_udp_unittest.cc

 // Copyright (c) 2012 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 "content/browser/renderer_host/p2p/socket_host_udp.h"
 
 #include <deque>
 #include <vector>
 
 #include "base/logging.h"
@@ skipping 355 matching lines @@
   // This packet will be dropped, as limit only for a single packet.
   socket_host_->Send(dest3, packet1, options, 0);
   net::IPEndPoint dest4 = ParseAddress(kTestIpAddress1, 2224);
   // This packet should also be dropped.
   socket_host_->Send(dest4, packet1, options, 0);
   // |dest1| is known, we can send as many packets to it.
   socket_host_->Send(dest1_, packet1, options, 0);
   ASSERT_EQ(sent_packets_.size(), 4U);
 }
 
+TEST_F(P2PSocketHostUdpTest, PackUnpackCallRecord) {
+  uint64 packet_id_result;
+  uint64 ticks_diff;
+  uint64 random_prefix = 0xabcd1234uLL << 32;
+  ASSERT_EQ(random_prefix & ((1uLL << 32) - 1), 0uL);
+
+  uint64 packet_id = 12;
+  uint64 ticks_now = 12345;
+  uint64 call_record =
+      P2PSocketHostUdp::PackCallRecord(random_prefix + packet_id, ticks_now);
+  EXPECT_EQ(call_record, (ticks_now << 32) + packet_id);
+
+  // Increment the tick by 2.
+  P2PSocketHostUdp::UnpackCallRecord(call_record,
+                                     random_prefix,
+                                     ticks_now + 2,
+                                     &packet_id_result,
+                                     &ticks_diff);
+  EXPECT_EQ(packet_id_result, random_prefix + packet_id);
+  EXPECT_EQ(ticks_diff, 2uL);
+
+  // Try a large packet id and the tick is rounding over 2^32.
+  packet_id = 0xffffffff;
+  ticks_now = 0xffffff00;
+  call_record =
+      P2PSocketHostUdp::PackCallRecord(random_prefix + packet_id, ticks_now);
+  EXPECT_EQ(call_record, (ticks_now << 32) + 0xffffffff);
+  P2PSocketHostUdp::UnpackCallRecord(call_record,
+                                     random_prefix,
+                                     ticks_now + 0x150,
+                                     &packet_id_result,
+                                     &ticks_diff);
+  EXPECT_EQ(packet_id_result, random_prefix + packet_id);
+  EXPECT_EQ(ticks_diff, 0x150uL);
+}
+
 }  // namespace content