Remove the usage of BrowserThread::FILE in web_ui_user_script_loader.cc

extensions/browser/user_script_loader.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 EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
 #define EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_
 
 #include <map>
 #include <memory>
 #include <set>
@@ skipping 24 matching lines @@
 // Manages one "logical unit" of user scripts in shared memory by constructing a
 // new shared memory region when the set of scripts changes. Also notifies
 // renderers of new shared memory region when new renderers appear, or when
 // script reloading completes. Script loading lives on the UI thread. Instances
 // of this class are embedded within classes with names ending in
 // UserScriptMaster. These "master" classes implement the strategy for which
 // scripts to load/unload on this logical unit of scripts.
 class UserScriptLoader : public content::NotificationObserver {
  public:
   using LoadScriptsCallback =
-      base::Callback<void(std::unique_ptr<UserScriptList>,
-                          std::unique_ptr<base::SharedMemory>)>;
+      base::OnceCallback<void(std::unique_ptr<UserScriptList>,
+                              std::unique_ptr<base::SharedMemory>)>;
   class Observer {
    public:
     virtual void OnScriptsLoaded(UserScriptLoader* loader) = 0;
     virtual void OnUserScriptLoaderDestroyed(UserScriptLoader* loader) = 0;
   };
 
   // Parses the includes out of |script| and returns them in |includes|.
   static bool ParseMetadataHeader(const base::StringPiece& script_text,
                                   UserScript* script);
 
@@ skipping 124 matching lines @@
   base::ObserverList<Observer> observers_;
 
   base::WeakPtrFactory<UserScriptLoader> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(UserScriptLoader);
 };
 
 }  // namespace extensions
 
 #endif  // EXTENSIONS_BROWSER_USER_SCRIPT_LOADER_H_