[NaCl SDK] Add comments in the implementation code of GoogleDriveFs

native_client_sdk/src/libraries/nacl_io/googledrivefs/googledrivefs_node.cc

 // Copyright 2016 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.
 
 #include "nacl_io/googledrivefs/googledrivefs_node.h"
 
 #include <sys/stat.h>
 
 #include "nacl_io/googledrivefs/googledrivefs.h"
 #include "nacl_io/kernel_handle.h"
 #include "nacl_io/node.h"
 #include "nacl_io/osdirent.h"
 
 namespace nacl_io {
 
+// This is not further implemented.
+// PNaCl is on a path to deprecation, and WebAssembly is
+// the focused technology.
+
 GoogleDriveFsNode::GoogleDriveFsNode(GoogleDriveFs* googledrivefs)
     : Node(googledrivefs) {}
 
 Error GoogleDriveFsNode::GetDents(size_t offs,
                                   struct dirent* pdir,
                                   size_t size,
                                   int* out_bytes) {
   // TODO: support getdents
   LOG_ERROR("getdents not supported.");
   return EPERM;
@@ skipping 35 matching lines @@
   return EPERM;
 }
 
 Error GoogleDriveFsNode::Init(int open_flags) {
   // TODO: support init
   LOG_ERROR("init not supported.");
   return EPERM;
 }
 
 }  // namespace nacl_io