[NaCl SDK] nacl_io: Fix excess realloc'ing in memfs nodes.

native_client_sdk/src/libraries/nacl_io/memfs/mem_fs.cc

 // 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.
 
 #include "nacl_io/memfs/mem_fs.h"
 
 #include <errno.h>
 #include <fcntl.h>
 
 #include <string>
@@ skipping 96 matching lines @@
 
     // Directories can only be opened read-only.
     if (node->IsaDir() && (open_flags & 3) != O_RDONLY)
       return EISDIR;
 
     // If we were expected to create it exclusively, fail
     if (open_flags & O_EXCL)
       return EEXIST;
 
     if (open_flags & O_TRUNC)
-      static_cast<MemFsNode*>(node.get())->Resize(0);
+      node->FTruncate(0);
   }
 
   *out_node = node;
   return 0;
 }
 
 Error MemFs::Mkdir(const Path& path, int mode) {
   // We expect a Filesystem "absolute" path
   if (!path.IsAbsolute())
     return ENOENT;
@@ skipping 139 matching lines @@
   if (file_only && child->IsaDir())
     return EISDIR;
 
   if (remove_dir && child->ChildCount() > 0)
     return ENOTEMPTY;
 
   return parent->RemoveChild(path.Basename());
 }
 
 }  // namespace nacl_io