Add non-host functionality to the previews blacklist

components/previews/core/previews_black_list.h

Index: components/previews/core/previews_black_list.h
diff --git a/components/previews/core/previews_black_list.h b/components/previews/core/previews_black_list.h
index a1e36cc9033a2eb1b403f9cc71dee1e72a1e3508..ad192463f17372ea9b166b89fa643976b99d4584 100644
--- a/components/previews/core/previews_black_list.h
+++ b/components/previews/core/previews_black_list.h
@@ -63,53 +63,57 @@ class PreviewsBlackList {
   bool IsLoadedAndAllowed(const GURL& url, PreviewsType type) const;
 
   // Asynchronously deletes all entries in the in-memory black list. Informs
   // the backing store to delete entries between |begin_time| and |end_time|,
   // and reloads entries into memory from the backing store. If the embedder
   // passed in a null store, resets all history in the in-memory black list.
   void ClearBlackList(base::Time begin_time, base::Time end_time);
 
   // Returns a new PreviewsBlackListItem representing |host_name|. Adds the new
   // item to |black_list_item_map|.
-  static PreviewsBlackListItem* GetOrCreateBlackListItem(
+  static PreviewsBlackListItem* GetOrCreateBlackListItemForMap(
       BlackListItemMap* black_list_item_map,
       const std::string& host_name);
 
-  // Returns the PreviewsBlackListItem representing |host_name| in
-  // |black_list_item_map|. If there is no item for |host_name|, returns null.
-  static PreviewsBlackListItem* GetBlackListItem(
-      const BlackListItemMap& black_list_item_map,
-      const std::string& host_name);
+  // Returns a new PreviewsBlackListItem for the host indifferent black list
+  // that does not consider host name when determining eligibility.
+  static std::unique_ptr<PreviewsBlackListItem>
+  CreateHostIndifferentBlackListItem();
 
  private:
   // Synchronous version of AddPreviewNavigation method.
   void AddPreviewNavigationSync(const GURL& host_name,
                                 bool opt_out,
                                 PreviewsType type);
 
   // Synchronous version of ClearBlackList method.
   void ClearBlackListSync(base::Time begin_time, base::Time end_time);
 
   // Callback passed to the backing store when loading black list information.
-  // Moves the returned map into the in-memory black list and runs any
-  // outstanding tasks.
-  void LoadBlackListDone(std::unique_ptr<BlackListItemMap> black_list_item_map);
+  // Moves the |black_list_item_map| and |host_indifferent_black_list_item| into
+  // the in-memory black list and runs any outstanding tasks.
+  void LoadBlackListDone(
+      std::unique_ptr<BlackListItemMap> black_list_item_map,
+      std::unique_ptr<PreviewsBlackListItem> host_indifferent_black_list_item);
 
   // Called while waiting for the black list to be loaded from the backing
   // store.
   // Enqueues a task to run when when loading black list information has
   // completed. Maintains the order that tasks were called in.
   void QueuePendingTask(base::Closure callback);
 
   // Map maintaining the in-memory black list.
   std::unique_ptr<BlackListItemMap> black_list_item_map_;
 
+  // Host indifferent opt out history.
+  std::unique_ptr<PreviewsBlackListItem> host_indifferent_black_list_item_;
+
   // Whether the black list is done being loaded from the backing store.
   bool loaded_;
 
   // The time of the last opt out for this session.
   base::Optional<base::Time> last_opt_out_time_;
 
   // The backing store of the black list information.
   std::unique_ptr<PreviewsOptOutStore> opt_out_store_;
 
   // Callbacks to be run after loading information from the backing store has