[NaCl SDK] nacl_io: big refactor to return error value (errno).

native_client_sdk/src/libraries/nacl_io/mount_node_mem.h

Index: native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
diff --git a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
index 07acfe16d72c9be9c4a5f583e9ef5b47686bded8..6457014293c6b717ed7646a969cc5a08ee5251a0 100644
--- a/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
+++ b/native_client_sdk/src/libraries/nacl_io/mount_node_mem.h
@@ -16,9 +16,12 @@ class MountNodeMem : public MountNode {
 
  public:
   // Normal read/write operations on a file
-  virtual int Read(size_t offs, void* buf, size_t count);
-  virtual int Write(size_t offs, const void* buf, size_t count);
-  virtual int FTruncate(off_t size);
+  virtual Error Read(size_t offs, void* buf, size_t count, int* out_bytes);
+  virtual Error Write(size_t offs,
+                      const void* buf,
+                      size_t count,
+                      int* out_bytes);
+  virtual Error FTruncate(off_t size);
 
  private:
   char* data_;