Replaced DCHECK with CHECK to detect invalid socket usage.

net/socket/tcp_socket_win.cc

Index: net/socket/tcp_socket_win.cc
diff --git a/net/socket/tcp_socket_win.cc b/net/socket/tcp_socket_win.cc
index 35bfb9b0cbb41b18c769484788aa0d34149dcb89..7c80a31944a6ed643853bee4019c1db42fec84e9 100644
--- a/net/socket/tcp_socket_win.cc
+++ b/net/socket/tcp_socket_win.cc
@@ -492,7 +492,7 @@ int TCPSocketWin::Read(IOBuffer* buf,
   DCHECK(CalledOnValidThread());
   DCHECK_NE(socket_, INVALID_SOCKET);
   DCHECK(!waiting_read_);
-  DCHECK(read_callback_.is_null());
+  CHECK(read_callback_.is_null());
   DCHECK(!core_->read_iobuffer_);
 
   return DoRead(buf, buf_len, callback);
@@ -504,7 +504,7 @@ int TCPSocketWin::Write(IOBuffer* buf,
   DCHECK(CalledOnValidThread());
   DCHECK_NE(socket_, INVALID_SOCKET);
   DCHECK(!waiting_write_);
-  DCHECK(write_callback_.is_null());
+  CHECK(write_callback_.is_null());
   DCHECK_GT(buf_len, 0);
   DCHECK(!core_->write_iobuffer_);