Migrate invalidator client IDs out of sync

chrome/common/pref_names.cc

Index: chrome/common/pref_names.cc
diff --git a/chrome/common/pref_names.cc b/chrome/common/pref_names.cc
index 7ae3cc01e0834439f3e319e65dc4b63ed2591d34..2ce8e0cc824ec4d01745315056909227d433be27 100644
--- a/chrome/common/pref_names.cc
+++ b/chrome/common/pref_names.cc
@@ -1714,6 +1714,9 @@ const char kSyncMaxInvalidationVersions[] = "sync.max_invalidation_versions";
 // disable/enable events.
 const char kSyncSessionsGUID[] = "sync.session_sync_guid";
 
+// An ID to uniquely identify this client to the invalidator service.
+const char kInvalidatorClientId[] = "invalidator.client_id";
+
 // Opaque state from the invalidation subsystem that is persisted via prefs.
 // The value is base 64 encoded.
 const char kInvalidatorInvalidationState[] = "invalidator.invalidation_state";