Add request throttler to thumbnail fetching for articles on mobile NTP

components/ntp_snippets/ntp_snippets_service.h

 // Copyright 2015 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 COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 #define COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_
 
 #include <stddef.h>
 
 #include <memory>
 #include <set>
 #include <string>
 #include <vector>
 
 #include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/timer/timer.h"
 #include "components/image_fetcher/image_fetcher_delegate.h"
 #include "components/ntp_snippets/category.h"
 #include "components/ntp_snippets/category_factory.h"
 #include "components/ntp_snippets/category_status.h"
 #include "components/ntp_snippets/content_suggestion.h"
 #include "components/ntp_snippets/content_suggestions_provider.h"
 #include "components/ntp_snippets/ntp_snippet.h"
 #include "components/ntp_snippets/ntp_snippets_fetcher.h"
 #include "components/ntp_snippets/ntp_snippets_scheduler.h"
 #include "components/ntp_snippets/ntp_snippets_status_service.h"
+#include "components/ntp_snippets/request_throttler.h"
 #include "components/suggestions/suggestions_service.h"
 #include "components/sync_driver/sync_service_observer.h"
 
 class PrefRegistrySimple;
 class PrefService;
 class SigninManagerBase;
 
 namespace base {
 class RefCountedMemory;
 class Value;
@@ skipping 51 matching lines @@
   // Returns whether the service is ready. While this is false, the list of
   // snippets will be empty, and all modifications to it (fetch, dismiss, etc)
   // will be ignored.
   bool ready() const { return state_ == State::READY; }
 
   // Returns whether the service is initialized. While this is false, some
   // calls may trigger DCHECKs.
   bool initialized() const { return ready() || state_ == State::DISABLED; }
 
   // Fetches snippets from the server and adds them to the current ones.
-  // Requests can be marked more important by setting |force_request| to true
-  // (such request might circumvent the daily quota for requests, etc.) Useful
-  // for requests triggered by the user.
-  void FetchSnippets(bool force_request);
+  // Requests can be marked more important by setting |interactive_request| to
+  // true (such request might circumvent the daily quota for requests, etc.)
+  // Useful for requests triggered by the user.
+  void FetchSnippets(bool interactive_request);
 
   // Fetches snippets from the server for specified hosts (overriding
   // suggestions from the suggestion service) and adds them to the current ones.
   // Only called from chrome://snippets-internals, DO NOT USE otherwise!
   // Ignored while |loaded()| is false.
   void FetchSnippetsFromHosts(const std::set<std::string>& hosts,
-                              bool force_request);
+                              bool interactive_request);
 
   // Available snippets.
   const NTPSnippet::PtrVector& snippets() const { return snippets_; }
 
   // Returns the list of snippets previously dismissed by the user (that are
   // not expired yet).
   const NTPSnippet::PtrVector& dismissed_snippets() const {
     return dismissed_snippets_;
   }
 
@@ skipping 179 matching lines @@
 
   // The service that provides events and data about the signin and sync state.
   std::unique_ptr<NTPSnippetsStatusService> snippets_status_service_;
 
   // Set to true if FetchSnippets is called before the database has been loaded.
   // The fetch will be executed after the database load finishes.
   bool fetch_after_load_;
 
   const Category provided_category_;
 
+  // Request throttler for limiting requests to thumbnail images.
+  RequestThrottler thumbnail_requests_throttler_;
+
   DISALLOW_COPY_AND_ASSIGN(NTPSnippetsService);
 };
 
 }  // namespace ntp_snippets
 
 #endif  // COMPONENTS_NTP_SNIPPETS_NTP_SNIPPETS_SERVICE_H_