Support providers with two namespaces

components/offline_items_collection/core/offline_item.h

Index: components/offline_items_collection/core/offline_item.h
diff --git a/components/offline_items_collection/core/offline_item.h b/components/offline_items_collection/core/offline_item.h
index 835311190fb155de2ca17eaa120335623808aa95..d05fc858e46c5e66215c420711c7e49c025b94ab 100644
--- a/components/offline_items_collection/core/offline_item.h
+++ b/components/offline_items_collection/core/offline_item.h
@@ -50,6 +50,8 @@ struct OfflineItem {
 
   bool operator==(const OfflineItem& offline_item) const;
 
+  bool operator<(const OfflineItem& offline_item) const;
+
   // The id of this OfflineItem.  Used to identify this item across all relevant
   // systems.
   ContentId id;