Issue 5013 - Mark more method as const

include/AdblockPlus/FilterEngine.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2017 eyeo GmbH
  *
  * Adblock Plus is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 3 as
  * published by the Free Software Foundation.
  *
  * Adblock Plus is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 324 matching lines @@
      * available even if subscription is not added yet.
      * @return Returns URL of the Acceptable Ads.
      */
     std::string GetAAUrl() const;
 
     /**
      * Invokes the listener set via SetNotificationAvailableCallback() with the
      * next notification to be shown.
      * @param url URL to match notifications to (optional).
      */
-    void ShowNextNotification(const std::string& url = std::string());
+    void ShowNextNotification(const std::string& url = std::string()) const;
 
     /**
      * Sets the callback invoked when a notification should be shown.
      * @param callback Callback to invoke.
      */
     void SetShowNotificationCallback(const ShowNotificationCallback& value);
 
     /**
      * Removes the callback invoked when a notification should be shown.
      */
@@ skipping 171 matching lines @@
     JsEnginePtr jsEngine;
     bool firstRun;
     int updateCheckId;
     static const std::map<ContentType, std::string> contentTypes;
 
     explicit FilterEngine(const JsEnginePtr& jsEngine);
 
     FilterPtr CheckFilterMatch(const std::string& url,
                                ContentTypeMask contentTypeMask,
                                const std::string& documentUrl) const;
-    void UpdateAvailable(UpdateAvailableCallback callback, JsValueList& params);
+    void UpdateAvailable(UpdateAvailableCallback callback, JsValueList& params) const;
     void UpdateCheckDone(const std::string& eventName,
                          UpdateCheckDoneCallback callback, JsValueList& params);
-    void FilterChanged(FilterChangeCallback callback, JsValueList& params);
+    void FilterChanged(FilterChangeCallback callback, JsValueList& params) const;
     void ShowNotification(const ShowNotificationCallback& callback,
-      const JsValueList& params);
+      const JsValueList& params) const;
     FilterPtr GetWhitelistingFilter(const std::string& url,
       ContentTypeMask contentTypeMask, const std::string& documentUrl) const;
     FilterPtr GetWhitelistingFilter(const std::string& url,
       ContentTypeMask contentTypeMask,
       const std::vector<std::string>& documentUrls) const;
   };
 }
 
 #endif