Supervised user blacklist: Don't download the blacklist file on every startup

chrome/browser/supervised_user/supervised_user_service.h

Index: chrome/browser/supervised_user/supervised_user_service.h
diff --git a/chrome/browser/supervised_user/supervised_user_service.h b/chrome/browser/supervised_user/supervised_user_service.h
index 11ac157d14290e498c1dbedd7e75d4ab7682a214..1f10b59b7b43b18cfaec5861fafc12e45badc39a 100644
--- a/chrome/browser/supervised_user/supervised_user_service.h
+++ b/chrome/browser/supervised_user/supervised_user_service.h
@@ -281,13 +281,17 @@ class SupervisedUserService : public KeyedService,
   void OnSiteListsChanged(
       const std::vector<scoped_refptr<SupervisedUserSiteList>>& site_lists);
 
-  // Asynchronously downloads a static blacklist file from |url|, stores it at
-  // |path|, loads it, and applies it to the URL filters. If |url| is not valid
-  // (e.g. empty), directly tries to load from |path|.
+  // Asynchronously loads a blacklist from a binary file at |path| and applies
+  // it to the URL filters. If no file exists at |path| yet, downloads a file
+  // from |url| and stores it at |path| first.
   void LoadBlacklist(const base::FilePath& path, const GURL& url);
 
-  // Asynchronously loads a static blacklist from a binary file at |path| and
-  // applies it to the URL filters.
+  void OnBlacklistFileChecked(const base::FilePath& path,
+                              const GURL& url,
+                              bool file_exists);
+
+  // Asynchronously loads a blacklist from a binary file at |path| and applies
+  // it to the URL filters.
   void LoadBlacklistFromFile(const base::FilePath& path);
 
   void OnBlacklistDownloadDone(const base::FilePath& path, bool success);