Detect situation when there is no missing send completion signal in P2PSocket implementation.

content/common/p2p_messages.h

 // 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.
 
 // IPC messages for the P2P Transport API.
 // Multiply-included message file, hence no include guard.
 
 #include "base/time/time.h"
 #include "content/common/content_export.h"
 #include "content/common/p2p_socket_type.h"
@@ skipping 31 matching lines @@
 IPC_STRUCT_TRAITS_BEGIN(rtc::PacketOptions)
   IPC_STRUCT_TRAITS_MEMBER(dscp)
   IPC_STRUCT_TRAITS_MEMBER(packet_time_params)
 IPC_STRUCT_TRAITS_END()
 
 IPC_STRUCT_TRAITS_BEGIN(content::P2PHostAndIPEndPoint)
   IPC_STRUCT_TRAITS_MEMBER(hostname)
   IPC_STRUCT_TRAITS_MEMBER(ip_address)
 IPC_STRUCT_TRAITS_END()
 
+IPC_STRUCT_TRAITS_BEGIN(content::P2PSendPacketMetrics)
+  IPC_STRUCT_TRAITS_MEMBER(packet_id)
+IPC_STRUCT_TRAITS_END()
+
 // P2P Socket messages sent from the browser to the renderer.
 
 IPC_MESSAGE_CONTROL1(P2PMsg_NetworkListChanged,
                      net::NetworkInterfaceList /* networks */)
 
 IPC_MESSAGE_CONTROL2(P2PMsg_GetHostAddressResult,
                      int32 /* request_id */,
                      net::IPAddressList /* address list*/)
 
 IPC_MESSAGE_CONTROL3(P2PMsg_OnSocketCreated,
                      int /* socket_id */,
                      net::IPEndPoint /* local_address */,
                      net::IPEndPoint /* remote_address */)
 
-IPC_MESSAGE_CONTROL1(P2PMsg_OnSendComplete,
-                     int /* socket_id */)
+// |send_metrics| carries packet_id for this packet.
+IPC_MESSAGE_CONTROL2(P2PMsg_OnSendComplete,
+                     int /* socket_id */,
+                     content::P2PSendPacketMetrics /* send_metrics */)
 
 IPC_MESSAGE_CONTROL1(P2PMsg_OnError,
                      int /* socket_id */)
 
 IPC_MESSAGE_CONTROL2(P2PMsg_OnIncomingTcpConnection,
                      int /* socket_id */,
                      net::IPEndPoint /* socket_address */)
 
 IPC_MESSAGE_CONTROL4(P2PMsg_OnDataReceived,
                      int /* socket_id */,
@@ skipping 31 matching lines @@
                      rtc::PacketOptions /* packet options */,
                      uint64 /* packet_id */)
 
 IPC_MESSAGE_CONTROL1(P2PHostMsg_DestroySocket,
                      int /* socket_id */)
 
 IPC_MESSAGE_CONTROL3(P2PHostMsg_SetOption,
                      int /* socket_id */,
                      content::P2PSocketOption /* socket option type */,
                      int /* value */)