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

native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc

Index: native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc
diff --git a/native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc b/native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc
index 9437675702c3862c54209ce1784e82663de74cd8..b5c19e228c2935d4d7d3a5642f8f1245fe82f459 100644
--- a/native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc
+++ b/native_client_sdk/src/libraries/nacl_io/pipe/pipe_event_emitter.cc
@@ -13,18 +13,19 @@ PipeEventEmitter::PipeEventEmitter(size_t size)
   UpdateStatus_Locked();
 }
 
-size_t PipeEventEmitter::Read_Locked(char* data, size_t len) {
-  size_t out_len = fifo_.Read(data, len);
+Error PipeEventEmitter::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 PipeEventEmitter::Write_Locked(const char* data, size_t len) {
-  size_t out_len = fifo_.Write(data, len);
+Error PipeEventEmitter::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