fileSystemProvider: First cut at implementing fileSystemProvider API

chrome/renderer/extensions/file_system_natives.h

 // Copyright (c) 2012 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 CHROME_RENDERER_EXTENSIONS_FILE_SYSTEM_NATIVES_H_
 #define CHROME_RENDERER_EXTENSIONS_FILE_SYSTEM_NATIVES_H_
 
 #include "base/compiler_specific.h"
 #include "chrome/renderer/extensions/object_backed_native_handler.h"
 
 namespace extensions {
 
 // Custom bindings for the nativeFileSystem API.
 class FileSystemNatives : public ObjectBackedNativeHandler {
  public:
   explicit FileSystemNatives(ChromeV8Context* context);
 
  private:
   void GetFileEntry(const v8::FunctionCallbackInfo<v8::Value>& args);
   void GetIsolatedFileSystem(const v8::FunctionCallbackInfo<v8::Value>& args);
   void CrackIsolatedFileSystemName(
       const v8::FunctionCallbackInfo<v8::Value>& args);
+  // Constructs a DOMError object to be used in JavaScript.
+  void GetDOMError(const v8::FunctionCallbackInfo<v8::Value>& args);
 
   DISALLOW_COPY_AND_ASSIGN(FileSystemNatives);
 };
 
 }  // namespace extensions
 
 #endif  // CHROME_RENDERER_EXTENSIONS_FILE_SYSTEM_NATIVES_H_