[NaCl SDK] nacl_io: Add flow control the JavaScript pipes.

native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc

Index: native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc b/native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc
index a130d5c3e149c109440cc65c2831439d4f6cfecc..4d5913a7b20b3077d68e94008fb4d695a754ca8f 100644
--- a/native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc
+++ b/native_client_sdk/src/libraries/nacl_io/devfs/tty_event_emitter.cc
@@ -13,18 +13,19 @@ TtyEventEmitter::TtyEventEmitter(size_t size)
   UpdateStatus_Locked();
 }
 
-size_t TtyEventEmitter::Read_Locked(char* data, size_t len) {
-  size_t out_len = fifo_.Read(data, len);
+Error TtyEventEmitter::Read_Locked(char* data, size_t len, int* out_bytes) {
+  *out_bytes = fifo_.Read(data, len);
 
   UpdateStatus_Locked();
-  return out_len;
+  return 0;
 }
 
-size_t TtyEventEmitter::Write_Locked(const char* data, size_t len) {
-  size_t out_len = fifo_.Write(data, len);
+Error TtyEventEmitter::Write_Locked(const char* data, size_t len,
+                                    int* out_bytes) {
+  *out_bytes = fifo_.Write(data, len);
 
   UpdateStatus_Locked();
-  return out_len;
+  return 0;
 }
 
 }  // namespace nacl_io