Issue #2230, #3391 - Load filters on "download begin" event

src/plugin/PluginTabBase.h

 /*
  * This file is part of Adblock Plus <https://adblockplus.org/>,
  * Copyright (C) 2006-2016 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 21 matching lines @@
   CriticalSection m_csInject;
 
   std::wstring m_documentDomain;
   std::wstring m_documentUrl;
   CPluginUserSettings m_pluginUserSettings;
   bool m_isActivated;
 
   std::thread m_thread;
   std::atomic<bool> m_continueThreadRunning;
 public:
-  CPluginFilter m_filter;
+  std::unique_ptr<CPluginFilter> filter;

[Eric, 2016/02/03 18:03:20]

As simple as this change looks, it's the core of the whole approach here. If the
member 'filter' is null, it means we need to load filters. If it's not, we skip
loading filters.

 private:
   void ThreadProc();
   CComAutoCriticalSection m_criticalSectionCache;
   std::set<std::wstring> m_cacheFrames;
   std::wstring m_cacheDomain;
   void InjectABP(IWebBrowser2* browser);
 public:
 
   CPluginTab();
   ~CPluginTab();
 
   std::wstring GetDocumentDomain();
   void SetDocumentUrl(const std::wstring& url);
   std::wstring GetDocumentUrl();
   virtual void OnActivate();
   virtual void OnUpdate();
   virtual void OnNavigate(const std::wstring& url);
+  void OnDownloadBegin();
   virtual void OnDownloadComplete(IWebBrowser2* browser);
   virtual void OnDocumentComplete(IWebBrowser2* browser, const std::wstring& url, bool isDocumentBrowser);
   static DWORD WINAPI TabThreadProc(LPVOID pParam);
   void CacheFrame(const std::wstring& url);
   bool IsFrameCached(const std::wstring& url);
   void ClearFrameCache(const std::wstring& domain=L"");
   /**
    * Is it possible to disable the current content of the present tab on a per-site basis?
    */
   bool IsPossibleToDisableOnSite();
 };
 
 #endif // _PLUGIN_TAB_BASE_H_