Mojo UDP: add a client-side wrapper which handles the client<->server buffering for users.

mojo/services/network/udp_socket_impl.cc

 // Copyright 2014 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 "mojo/services/network/udp_socket_impl.h"
 
 #include <string.h>
 
 #include <algorithm>
 #include <limits>
@@ skipping 64 matching lines @@
   }
 
   net::IPEndPoint bound_ip_end_point;
   NetAddressPtr bound_addr;
   net_result = socket_.GetLocalAddress(&bound_ip_end_point);
   if (net_result == net::OK)
     bound_addr = NetAddress::From(bound_ip_end_point);
 
   bound_ = true;
   callback.Run(MakeNetworkError(net::OK), bound_addr.Pass());
+
+  if (remaining_recv_slots_ > 0) {
+    DCHECK(!recvfrom_buffer_.get());
+    DoRecvFrom();
+  }
 }
 
 void UDPSocketImpl::SetSendBufferSize(
     uint32_t size,
     const Callback<void(NetworkErrorPtr)>& callback) {
   if (!bound_) {
     callback.Run(MakeNetworkError(net::ERR_FAILED));
     return;
   }
 
@@ skipping 36 matching lines @@
     pending_send_requests_.resize(max_pending_send_requests_);
     for (auto& discarded_request : discarded_requests) {
       discarded_request->callback.Run(
           MakeNetworkError(net::ERR_INSUFFICIENT_RESOURCES));
       delete discarded_request;
     }
   }
 }
 
 void UDPSocketImpl::ReceiveMore(uint32_t datagram_number) {
-  if (!bound_ || datagram_number == 0)
+  if (datagram_number == 0)
     return;
   if (std::numeric_limits<size_t>::max() - remaining_recv_slots_ <
           datagram_number) {
     return;
   }
 
   remaining_recv_slots_ += datagram_number;
 
-  if (!recvfrom_buffer_.get()) {
+  if (bound_ && !recvfrom_buffer_.get()) {
     DCHECK_EQ(datagram_number, remaining_recv_slots_);
     DoRecvFrom();
   }
 }
 
 void UDPSocketImpl::SendTo(NetAddressPtr dest_addr,
                            Array<uint8_t> data,
                            const Callback<void(NetworkErrorPtr)>& callback) {
   if (!bound_) {
     callback.Run(MakeNetworkError(net::ERR_FAILED));
@@ skipping 105 matching lines @@
   if (pending_send_requests_.empty())
     return;
 
   scoped_ptr<PendingSendRequest> request(pending_send_requests_.front());
   pending_send_requests_.pop_front();
 
   DoSendTo(request->addr.Pass(), request->data.Pass(), request->callback);
 }
 
 }  // namespace mojo