Use in-class initializers for base::WeakPtrFactory in components/.

Generated by: https://chromium-review.googlesource.com/c/chromium/src/+/1689216

Bug: 981415
Change-Id: I706ec55f1f533ef616f400791d69a51e9a151da1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1699508
Commit-Queue: Jeremy Roman <[email protected]>
Reviewed-by: Colin Blundell <[email protected]>
Cr-Commit-Position: refs/heads/master@{#677340}
diff --git a/components/sync_sessions/session_store.h b/components/sync_sessions/session_store.h
index 9cade4cb..71c33c9 100644
--- a/components/sync_sessions/session_store.h
+++ b/components/sync_sessions/session_store.h
@@ -170,7 +170,7 @@
 
   SyncedSessionTracker session_tracker_;
 
-  base::WeakPtrFactory<SessionStore> weak_ptr_factory_;
+  base::WeakPtrFactory<SessionStore> weak_ptr_factory_{this};
 
   DISALLOW_COPY_AND_ASSIGN(SessionStore);
 };