gin test - add simple file access for JS

gin/test/file.h

 // Copyright 2014 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 GIN_TEST_GC_H_
-#define GIN_TEST_GC_H_
+#ifndef GIN_TEST_FILE_H_
+#define GIN_TEST_FILE_H_
 
 #include "v8/include/v8.h"
 
 namespace gin {
 
-// This module provides bindings to the garbage collector.
-class GC {
+class File {
  public:
   static const char kModuleName[];
   static v8::Local<v8::Value> GetModule(v8::Isolate* isolate);
 };
 
 }  // namespace gin
 
-#endif  // GIN_TEST_GC_H_
+#endif  // GIN_TEST_FILE_H_
+