[NTP Tiles] Avoid duplicate requests from IconCacherImpl

components/ntp_tiles/icon_cacher_impl.h

Index: components/ntp_tiles/icon_cacher_impl.h
diff --git a/components/ntp_tiles/icon_cacher_impl.h b/components/ntp_tiles/icon_cacher_impl.h
index 52bd3fd373dcaa3397ddbcea0dd6a0872e57ac40..85d02b760f1e7ac6752aeecdfe85dfa62d3b5e07 100644
--- a/components/ntp_tiles/icon_cacher_impl.h
+++ b/components/ntp_tiles/icon_cacher_impl.h
@@ -6,7 +6,9 @@
 #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"
@@ -58,37 +60,39 @@ class IconCacherImpl : public IconCacher {
 
   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_;