[NTP Tiles] Avoid duplicate requests from IconCacherImpl

components/ntp_tiles/icon_cacher_impl.h

 // Copyright 2016 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_TILES_ICON_CACHER_IMPL_H_
 #define COMPONENTS_NTP_TILES_ICON_CACHER_IMPL_H_
 
 #include <memory>
+#include <set>
 #include <string>
+#include <vector>
 
 #include "base/callback.h"
 #include "base/cancelable_callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/task/cancelable_task_tracker.h"
 #include "components/ntp_tiles/icon_cacher.h"
 #include "components/ntp_tiles/popular_sites.h"
 
 namespace favicon {
 class FaviconService;
@@ skipping 31 matching lines @@
       const base::Closure& preliminary_icon_available) override;
   void StartFetchMostLikely(const GURL& page_url,
                             const base::Closure& icon_available) override;
 
  private:
   using CancelableImageCallback =
       base::CancelableCallback<void(const gfx::Image&)>;
 
   void OnGetFaviconImageForPageURLFinished(
       PopularSites::Site site,
-      const base::Closure& icon_available,
       const base::Closure& preliminary_icon_available,
       const favicon_base::FaviconImageResult& result);
 
   void OnPopularSitesFaviconDownloaded(
       PopularSites::Site site,
       std::unique_ptr<CancelableImageCallback> preliminary_callback,
-      const base::Closure& icon_available,
       const std::string& id,
       const gfx::Image& fetched_image,
       const image_fetcher::RequestMetadata& metadata);
 
   std::unique_ptr<CancelableImageCallback> MaybeProvideDefaultIcon(
       const PopularSites::Site& site,
-      const base::Closure& icon_available);
-  void SaveAndNotifyIconForSite(const PopularSites::Site& site,
-                                const base::Closure& icon_available,
-                                const gfx::Image& image);
+      const base::Closure& preliminary_icon_available);
+  void SaveAndNotifyDefaultIconForSite(
+      const PopularSites::Site& site,
+      const base::Closure& preliminary_icon_available,
+      const gfx::Image& image);
+  void SaveIconForSite(const PopularSites::Site& site, const gfx::Image& image);
 
   void OnGetLargeIconOrFallbackStyleFinished(
       const GURL& page_url,
-      const base::Closure& icon_available,
       const favicon_base::LargeIconResult& result);
 
-  void OnMostLikelyFaviconDownloaded(const base::Closure& icon_available,
-                                     bool success);
+  bool StartRequest(const GURL& request_url,
+                    const base::Closure& icon_available);
+  void FinishRequestAndNotifyIconAvailable(const GURL& request_url,
+                                           bool newly_available);
 
   base::CancelableTaskTracker tracker_;
   favicon::FaviconService* const favicon_service_;
   favicon::LargeIconService* const large_icon_service_;
   std::unique_ptr<image_fetcher::ImageFetcher> const image_fetcher_;
+  std::map<GURL, std::vector<base::Closure>> in_flight_requests_;
 
   base::WeakPtrFactory<IconCacherImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(IconCacherImpl);
 };
 
 }  // namespace ntp_tiles
 
 #endif  // COMPONENTS_NTP_TILES_ICON_CACHER_IMPL_H_