DCHECK -> CHECK for UDPSocket Read/Write calls when previouse in progress.

net/udp/udp_socket_libevent.cc

Index: net/udp/udp_socket_libevent.cc
diff --git a/net/udp/udp_socket_libevent.cc b/net/udp/udp_socket_libevent.cc
index 7db3f96dd128fb1f6d8c61e951b37455f0349fe4..9b1a9957189d968c3fed617ba02aa3ee7d13cb98 100644
--- a/net/udp/udp_socket_libevent.cc
+++ b/net/udp/udp_socket_libevent.cc
@@ -170,7 +170,7 @@ int UDPSocketLibevent::RecvFrom(IOBuffer* buf,
                                 const CompletionCallback& callback) {
   DCHECK(CalledOnValidThread());
   DCHECK_NE(kInvalidSocket, socket_);
-  DCHECK(read_callback_.is_null());
+  CHECK(read_callback_.is_null());

[wtc, 2014/09/24 15:10:07]

Ryan: I think it would be better to add a new net error
code, say ERR_BUSY or ERR_IN_USE, and make these functions
return that error code rather than crashing with a CHECK
failure:

  if (!read_callback_.is_null())
    return ERR_BUSY;

   DCHECK(!recv_from_address_);
   DCHECK(!callback.is_null());  // Synchronous operation not supported
   DCHECK_GT(buf_len, 0);
@@ -214,7 +214,7 @@ int UDPSocketLibevent::SendToOrWrite(IOBuffer* buf,
                                      const CompletionCallback& callback) {
   DCHECK(CalledOnValidThread());
   DCHECK_NE(kInvalidSocket, socket_);
-  DCHECK(write_callback_.is_null());
+  CHECK(write_callback_.is_null());
   DCHECK(!callback.is_null());  // Synchronous operation not supported
   DCHECK_GT(buf_len, 0);