Index: components/sync/user_events/global_id_mapper.h |
diff --git a/components/sync/user_events/global_id_mapper.h b/components/sync/user_events/global_id_mapper.h |
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+// Copyright 2017 The Chromium Authors. All rights reserved. |
+// Use of this source code is governed by a BSD-style license that can be |
+// found in the LICENSE file. |
+ |
+#ifndef COMPONENTS_SYNC_USER_EVENTS_GLOBAL_ID_MAPPER_H_ |
+#define COMPONENTS_SYNC_USER_EVENTS_GLOBAL_ID_MAPPER_H_ |
+ |
+#include <stdint.h> |
+ |
+#include "base/callback.h" |
+ |
+namespace syncer { |
+ |
+using GlobalIdChange = |
+ base::RepeatingCallback<void(int64_t old_global_id, int64_t new_global_id)>; |
+ |
+// UserEventSpecifics references SESSIONS data through their |navigation_id| |
+// which will match values seen in TabNavigation's |global_id|. This field is |
+// really just the timestamp from the NavigationEntry, which can change when a |
+// page is reloaded. This will cause the SESSIONS side to override the old data. |
+// The impact to USER_EVENTS depends on if the previous timestamp made it to the |
+// server as part of SESSIONS data or not. If it did not, then USER_EVENTS must |
+// be updated. But knowing the answer that question is currently very tricky |
+// with Sync's current architecture, so instead we always update for uncommitted |
+// USER_EVENTS. The purpose of the GlobalIdMapper is the track changes in the |
+// SESSIONS' |global_id| field and feed this information the USER_EVENTS side. |
+class GlobalIdMapper { |
+ public: |
+ // Register for information about changing |
+ virtual void AddGlobalIdChangeObserver(GlobalIdChange callback) = 0; |
+ |
+ // Given a |global_id|, returns what the latest global_id is for the given |
+ // navigation, to the best of our ability. If we do not have such a mapping, |
+ // which is quite possible, the input |global_id| is returned. |
+ virtual int64_t GetLatestGlobalId(int64_t global_id) = 0; |
+}; |
+ |
+} // namespace syncer |
+ |
+#endif // COMPONENTS_SYNC_USER_EVENTS_GLOBAL_ID_MAPPER_H_ |