Revert of NTP Zombie Code Slayer Part IV: Most Visited

chrome/browser/ui/webui/ntp/most_visited_handler.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_BROWSER_UI_WEBUI_NTP_MOST_VISITED_HANDLER_H_
+#define CHROME_BROWSER_UI_WEBUI_NTP_MOST_VISITED_HANDLER_H_
+
+#include <string>
+#include <vector>
+
+#include "base/memory/weak_ptr.h"
+#include "base/scoped_observer.h"
+#include "components/history/core/browser/history_types.h"
+#include "components/history/core/browser/top_sites_observer.h"
+#include "content/public/browser/web_ui_message_handler.h"
+
+class GURL;
+
+namespace base {
+class ListValue;
+class Value;
+}
+
+namespace user_prefs {
+class PrefRegistrySyncable;
+}
+
+// The handler for Javascript messages related to the "most visited" view.
+//
+// This class manages one preference:
+// - The URL blacklist: URLs we do not want to show in the thumbnails list.  It
+//   is a dictionary for quick access (it associates a dummy boolean to the URL
+//   string).
+class MostVisitedHandler : public content::WebUIMessageHandler,
+                           public history::TopSitesObserver {
+ public:
+
+  MostVisitedHandler();
+  ~MostVisitedHandler() override;
+
+  // WebUIMessageHandler override and implementation.
+  void RegisterMessages() override;
+
+  // Callback for the "getMostVisited" message.
+  void HandleGetMostVisited(const base::ListValue* args);
+
+  // Callback for the "blacklistURLFromMostVisited" message.
+  void HandleBlacklistUrl(const base::ListValue* args);
+
+  // Callback for the "removeURLsFromMostVisitedBlacklist" message.
+  void HandleRemoveUrlsFromBlacklist(const base::ListValue* args);
+
+  // Callback for the "clearMostVisitedURLsBlacklist" message.
+  void HandleClearBlacklist(const base::ListValue* args);
+
+  // Callback for the "mostVisitedAction" message.
+  void HandleMostVisitedAction(const base::ListValue* args);
+
+  // Callback for the "mostVisitedSelected" message.
+  void HandleMostVisitedSelected(const base::ListValue* args);
+
+  const std::vector<GURL>& most_visited_urls() const {
+    return most_visited_urls_;
+  }
+
+  static void RegisterProfilePrefs(user_prefs::PrefRegistrySyncable* registry);
+
+ private:
+  struct MostVisitedPage;
+
+  // Send a request to the HistoryService to get the most visited pages.
+  void StartQueryForMostVisited();
+
+  // Sets pages_value_ from a format produced by TopSites.
+  void SetPagesValueFromTopSites(const history::MostVisitedURLList& data);
+
+  // Callback for TopSites.
+  void OnMostVisitedUrlsAvailable(const history::MostVisitedURLList& data);
+
+  // Puts the passed URL in the blacklist (so it does not show as a thumbnail).
+  void BlacklistUrl(const GURL& url);
+
+  // Returns the key used in url_blacklist_ for the passed |url|.
+  std::string GetDictionaryKeyForUrl(const std::string& url);
+
+  // Sends pages_value_ to the javascript side and resets page_value_.
+  void SendPagesValue();
+
+  // history::TopSitesObserver implementation.
+  void TopSitesLoaded(history::TopSites* top_sites) override;
+  void TopSitesChanged(history::TopSites* top_sites) override;
+
+  // Scoped observer to help with TopSitesObserver registration.
+  ScopedObserver<history::TopSites, history::TopSitesObserver> scoped_observer_;
+
+  // The most visited URLs, in priority order.
+  // Only used for matching up clicks on the page to which most visited entry
+  // was clicked on for metrics purposes.
+  std::vector<GURL> most_visited_urls_;
+
+  // We pre-fetch the first set of result pages.  This variable is false until
+  // we get the first getMostVisited() call.
+  bool got_first_most_visited_request_;
+
+  // Keep the results of the db query here.
+  scoped_ptr<base::ListValue> pages_value_;
+
+  // Whether the user has viewed the 'most visited' pane.
+  bool most_visited_viewed_;
+
+  // Whether the user has performed a "tracked" action to leave the page or not.
+  bool user_action_logged_;
+
+  // For callbacks which may be run after destruction.
+  base::WeakPtrFactory<MostVisitedHandler> weak_ptr_factory_;
+
+  DISALLOW_COPY_AND_ASSIGN(MostVisitedHandler);
+};
+
+#endif  // CHROME_BROWSER_UI_WEBUI_NTP_MOST_VISITED_HANDLER_H_