Factor out duplicated GioMemoryFileSnapshotCtor() + NaClAppLoadFile() calls

src/shared/gio/gio_mem_snapshot.c

 /*
  * Copyright (c) 2012 The Native Client Authors. All rights reserved.
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 /*
  * NaCl Generic I/O interface implementation: in-memory snapshot of a file.
  */
 
 #include "native_client/src/include/portability.h"
 #include <stdio.h>
 #include <sys/stat.h>
 #include <stdlib.h>
 
 #include "native_client/src/shared/gio/gio.h"
 
 struct GioVtbl const  kGioMemoryFileSnapshotVtbl = {
   GioMemoryFileSnapshotDtor,
   GioMemoryFileRead,
   GioMemoryFileWrite,
   GioMemoryFileSeek,
   GioMemoryFileFlush,
   GioMemoryFileClose,
 };
 
 
 int   GioMemoryFileSnapshotCtor(struct GioMemoryFileSnapshot  *self,
-                                char                          *fn) {
+                                const char                    *filename) {
   FILE            *iop;
   struct stat     stbuf;
   char            *buffer;
 
   ((struct Gio *) self)->vtbl = (struct GioVtbl *) NULL;
-  if (0 == (iop = fopen(fn, "rb"))) {
+  if (0 == (iop = fopen(filename, "rb"))) {
     return 0;
   }
   if (fstat(fileno(iop), &stbuf) == -1) {
  abort0:
     fclose(iop);
     return 0;
   }
   if (0 == (buffer = malloc(stbuf.st_size))) {
     goto abort0;
   }
@@ skipping 11 matching lines @@
   return 1;
 }
 
 
 void GioMemoryFileSnapshotDtor(struct Gio                     *vself) {
   struct GioMemoryFileSnapshot  *self = (struct GioMemoryFileSnapshot *)
       vself;
   free(self->base.buffer);
   GioMemoryFileDtor(vself);
 }