nacl_io: Add SOCK_DGRAM support to socketpair()

native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h

Index: native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h
diff --git a/native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h b/native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h
index e8ba0b3c38423237b694f48c92e6c489cd534d0b..30a25a90f058640194c805c6f35876fa5213e94a 100644
--- a/native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h
+++ b/native_client_sdk/src/libraries/nacl_io/socket/fifo_packet.h
@@ -5,6 +5,7 @@
 #ifndef LIBRARIES_NACL_IO_FIFO_PACKET_H_
 #define LIBRARIES_NACL_IO_FIFO_PACKET_H_
 
+#include <stdint.h>
 #include <string.h>
 
 #include <list>
@@ -45,6 +46,12 @@ class FIFOPacket : public FIFOInterface {
   // Take ownership of packet and place it in the FIFO.
   void WritePacket(Packet* packet);
 
+  // Read out the top packet into a byte buffer.
+  size_t Read(void* buf, size_t len);
+
+  // Enqueue a new packet from a byte buffer.
+  size_t Write(const void* buf, size_t len);
+
  private:
   std::list<Packet*> packets_;
   uint32_t max_bytes_;