[Sync] Componentize synced_tab_delegate

chrome/browser/sync/glue/synced_session_tracker.h

Index: chrome/browser/sync/glue/synced_session_tracker.h
diff --git a/chrome/browser/sync/glue/synced_session_tracker.h b/chrome/browser/sync/glue/synced_session_tracker.h
index 59946b86ea0f023e599bb30a5bebdd8d7105047b..cf2afdca8da6be63002707676e11fdcbfcedd8d9 100644
--- a/chrome/browser/sync/glue/synced_session_tracker.h
+++ b/chrome/browser/sync/glue/synced_session_tracker.h
@@ -16,6 +16,10 @@
 #include "components/sync_driver/glue/synced_session.h"
 #include "components/sync_driver/tab_node_pool.h"
 
+namespace sync_sessions {
+class SyncSessionsClient;
+}
+
 namespace browser_sync {
 
 // Class to manage synced sessions. The tracker will own all SyncedSession
@@ -25,7 +29,8 @@ namespace browser_sync {
 // the local session (whose tag we maintain separately).
 class SyncedSessionTracker {
  public:
-  SyncedSessionTracker();
+  explicit SyncedSessionTracker(
+      sync_sessions::SyncSessionsClient* sessions_client);
   ~SyncedSessionTracker();
 
   // We track and distinguish the local session from foreign sessions.
@@ -223,6 +228,9 @@ class SyncedSessionTracker {
                                    SessionID::id_type tab_id,
                                    int tab_node_id);
 
+  // The client of the sync sessions datatype.
+  sync_sessions::SyncSessionsClient* const sessions_client_;
+
   // Per client mapping of tab id's to their SessionTab objects.
   // Key: session tag.
   // Value: Tab id to SessionTabWrapper map.