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chrome/browser/web_resource/web_resource_service.h

 // Copyright (c) 2011 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_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
 #define CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_
 #pragma once
 
 #include <string>
 
-#include "content/browser/utility_process_host.h"
-#include "content/public/browser/notification_types.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "content/public/common/url_fetcher_delegate.h"
 
 class PrefService;
 class ResourceDispatcherHost;
 
 namespace base {
 class DictionaryValue;
 }
 
-// A WebResourceService fetches data from a web resource server and store
-// locally as user preference.
-class WebResourceService : public UtilityProcessHost::Client {
+// A WebResourceService fetches JSON data from a web server and periodically
+// refreshes it.
+class WebResourceService
+    : public base::RefCountedThreadSafe<WebResourceService>,
+      public content::URLFetcherDelegate {
  public:
-  // Pass notification_type = NOTIFICATION_TYPE_COUNT if notification is not
-  // required.
   WebResourceService(PrefService* prefs,
                      const char* web_resource_server,
                      bool apply_locale_to_url_,
-                     int notification_type,
                      const char* last_update_time_pref_name,
-                     int start_fetch_delay,
-                     int cache_update_delay);
+                     int start_fetch_delay_ms,
+                     int cache_update_delay_ms);
 
-  // Sleep until cache needs to be updated, but always for at least 5 seconds
-  // so we don't interfere with startup.  Then begin updating resources.
-  void StartAfterDelay();
-
-  // We have successfully pulled data from a resource server; now launch
-  // the process that will parse the JSON, and then update the cache.
-  void UpdateResourceCache(const std::string& json_data);
+  // Sleep until cache needs to be updated, but always for at least
+  // |start_fetch_delay_ms| so we don't interfere with startup.
+  // Then begin updating resources.
+  // TODO(bauerb): Comment
+  bool StartAfterDelay(bool only_if_necessary);
 
  protected:
   virtual ~WebResourceService();
+  friend class base::RefCountedThreadSafe<WebResourceService>;
+
+  // TODO(bauerb): comment
+  static void RegisterLastUpdateTimePref(PrefService* prefs,
+                                         const char* pref_name);
 
   virtual void Unpack(const base::DictionaryValue& parsed_json) = 0;
 
-  // If delay_ms is positive, schedule notification with the delay.
-  // If delay_ms is 0, notify immediately by calling WebResourceStateChange().
-  // If delay_ms is negative, do nothing.
-  void PostNotification(int64 delay_ms);
-
   // We need to be able to load parsed resource data into preferences file,
   // and get proper install directory.
   PrefService* prefs_;
 
  private:
-  class WebResourceFetcher;
-  friend class WebResourceFetcher;
-
   class UnpackerClient;
 
-  // Set in_fetch_ to false, clean up temp directories (in the future).
+  // content::URLFetcherDelegate implementation:
+  virtual void OnURLFetchComplete(const content::URLFetcher* source) OVERRIDE;
+
+  // Schedules a fetch after |delay_ms| milliseconds.
+  void ScheduleFetch(int64 delay_ms);
+
+  // Starts fetching data from the server.
+  void StartFetch();
+
+  // Set |in_fetch_| to false, clean up temp directories (in the future).
   void EndFetch();
 
-  // Puts parsed json data in the right places, and writes to prefs file.
-  void OnWebResourceUnpacked(const base::DictionaryValue& parsed_json);
+  // So that we can delay our start so as not to affect start-up time; also,
+  // so that we can schedule future cache updates.
+  base::WeakPtrFactory<WebResourceService> weak_ptr_factory_;
 
-  // Notify listeners that the state of a web resource has changed.
-  void WebResourceStateChange();
+  // The tool that fetches the url data from the server.
+  scoped_ptr<content::URLFetcher> url_fetcher_;
 
-  scoped_ptr<WebResourceFetcher> web_resource_fetcher_;
-
-  ResourceDispatcherHost* resource_dispatcher_host_;
-
-  // Allows the creation of tasks to send a WEB_RESOURCE_STATE_CHANGED
-  // notification. This allows the WebResourceService to notify the New Tab
-  // Page immediately when a new web resource should be shown or removed.
-  ScopedRunnableMethodFactory<WebResourceService> service_factory_;
-
-  // True if we are currently mid-fetch.  If we are asked to start a fetch
-  // when we are still fetching resource data, schedule another one in
-  // kCacheUpdateDelay time, and silently exit.
+  // True if we are currently fetching or unpacking data. If we are asked to
+  // start a fetch when we are still fetching resource data, schedule another
+  // one in |cache_update_delay_ms_| time, and silently exit.
   bool in_fetch_;
 
   // URL that hosts the web resource.
   const char* web_resource_server_;
 
   // Indicates whether we should append locale to the web resource server URL.
   bool apply_locale_to_url_;
 
-  // Notification type when an update is done.
-  int notification_type_;
-
   // Pref name to store the last update's time.
   const char* last_update_time_pref_name_;
 
   // Delay on first fetch so we don't interfere with startup.
-  int start_fetch_delay_;
+  int start_fetch_delay_ms_;
 
   // Delay between calls to update the web resource cache. This delay may be
   // different for different builds of Chrome.
-  int cache_update_delay_;
-
-  // True if a task has been set to update the cache when a new web resource
-  // becomes available.
-  bool web_resource_update_scheduled_;
+  int cache_update_delay_ms_;
 
   DISALLOW_COPY_AND_ASSIGN(WebResourceService);
 };
 
 #endif  // CHROME_BROWSER_WEB_RESOURCE_WEB_RESOURCE_SERVICE_H_