Plumbing though mode parameter to open, since fusefs can make use of it.

native_client_sdk/src/libraries/nacl_io/stream/stream_fs.h

 // Copyright 2013 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef LIBRARIES_NACL_IO_STREAM_STREAM_H_
 #define LIBRARIES_NACL_IO_STREAM_STREAM_H_
 
 #include "nacl_io/filesystem.h"
 
 #include "ppapi/c/pp_completion_callback.h"
@@ skipping 36 matching lines @@
   void EnqueueWork(Work* work);
 
   // Returns a completion callback which will execute the StartWork member
   // of a MountSocketWork object.
   static PP_CompletionCallback GetStartCompletion(Work* work);
 
   // Returns a completion callback which will execute the RunCallback member
   // of a MountSocketWork object.
   static PP_CompletionCallback GetRunCompletion(Work* work);
 
-  virtual Error Open(const Path& path, int o_flags, ScopedNode* out_node);
+  virtual Error OpenWithMode(const Path& path, int o_flags, mode_t mode,
+                             ScopedNode* out_node);
   virtual Error Unlink(const Path& path);
   virtual Error Mkdir(const Path& path, int permissions);
   virtual Error Rmdir(const Path& path);
   virtual Error Remove(const Path& path);
   virtual Error Rename(const Path& path, const Path& newpath);
 
   static void* StreamThreadThunk(void*);
   void StreamThread();
 
  private:
   PP_Resource message_loop_;
   pthread_cond_t message_cond_;
   sdk_util::SimpleLock message_lock_;
 
   friend class KernelProxy;
   DISALLOW_COPY_AND_ASSIGN(StreamFs);
 };
 
 }  // namespace nacl_io
 
 #endif  // LIBRARIES_NACL_IO_STREAM_STREAM_H_