Flush Channel IDs when Cookies get saved to a persistent backend

net/ssl/channel_id_store.h

Index: net/ssl/channel_id_store.h
diff --git a/net/ssl/channel_id_store.h b/net/ssl/channel_id_store.h
index abd09f6430113c715ba281d52124ead37fd2caf1..8767cd6ef2e35112890a41c790e16831e9568c03 100644
--- a/net/ssl/channel_id_store.h
+++ b/net/ssl/channel_id_store.h
@@ -95,6 +95,9 @@ class NET_EXPORT ChannelIDStore
   // Returns all channel ID keypairs.
   virtual void GetAllChannelIDs(const GetChannelIDListCallback& callback) = 0;
 
+  // Signals to the backing store that any pending writes should be flushed.
+  virtual void Flush() = 0;
+
   // Helper function that adds all keypairs from |list| into this instance.
   void InitializeFrom(const ChannelIDList& list);