Move UseNonBlockingIO from a windows-only method

net/udp/udp_server_socket.h

Index: net/udp/udp_server_socket.h
diff --git a/net/udp/udp_server_socket.h b/net/udp/udp_server_socket.h
index a0b4852b958740e9d3fb6c6d0fb1d3eee4cbf934..dcb57143669c79e254a86137d95862108fe2d40b 100644
--- a/net/udp/udp_server_socket.h
+++ b/net/udp/udp_server_socket.h
@@ -39,6 +39,7 @@ class NET_EXPORT UDPServerSocket : public DatagramServerSocket {
   void Close() override;
   int GetPeerAddress(IPEndPoint* address) const override;
   int GetLocalAddress(IPEndPoint* address) const override;
+  void UseNonBlockingIO() override;
   const BoundNetLog& NetLog() const override;
   void AllowAddressReuse() override;
   void AllowBroadcast() override;
@@ -50,12 +51,6 @@ class NET_EXPORT UDPServerSocket : public DatagramServerSocket {
   int SetDiffServCodePoint(DiffServCodePoint dscp) override;
   void DetachFromThread() override;
 
-#if defined(OS_WIN)
-  // Switch to use non-blocking IO. Must be called right after construction and
-  // before other calls.
-  void UseNonBlockingIO();
-#endif
-
  private:
   UDPSocket socket_;
   bool allow_address_reuse_;