chrome: Cleanup class/struct forward declarations

chrome/browser/extensions/api/file_handlers/directory_util.h

 // 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.
 
 #ifndef CHROME_BROWSER_EXTENSIONS_API_FILE_HANDLERS_DIRECTORY_UTIL_H_
 #define CHROME_BROWSER_EXTENSIONS_API_FILE_HANDLERS_DIRECTORY_UTIL_H_
 
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback.h"
 #include "base/macros.h"
 #include "base/memory/weak_ptr.h"
 
 class Profile;
 
 namespace base {
 class FilePath;
 }  // namespace base
 
-namespace storage {
-class FileSystemURL;
-}  // namespace storage
-
 namespace extensions {
 namespace app_file_handler_util {
 
 class IsDirectoryCollector {
  public:
   typedef base::Callback<void(std::unique_ptr<std::set<base::FilePath>>)>
       CompletionCallback;
 
   explicit IsDirectoryCollector(Profile* profile);
   virtual ~IsDirectoryCollector();
@@ skipping 13 matching lines @@
   CompletionCallback callback_;
   base::WeakPtrFactory<IsDirectoryCollector> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IsDirectoryCollector);
 };
 
 }  // namespace app_file_handler_util
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_HANDLERS_DIRECTORY_UTIL_H_