[Sync] Make SESSIONS an implicit type

chrome/browser/sync/sync_prefs_unittest.cc

Index: chrome/browser/sync/sync_prefs_unittest.cc
diff --git a/chrome/browser/sync/sync_prefs_unittest.cc b/chrome/browser/sync/sync_prefs_unittest.cc
index 79b24d5e1f5154f3214a2bc43aa6d6045269c927..2d623947cce18e9392d819e913e05be2e2ff2f6a 100644
--- a/chrome/browser/sync/sync_prefs_unittest.cc
+++ b/chrome/browser/sync/sync_prefs_unittest.cc
@@ -39,6 +39,8 @@ syncer::ModelTypeSet GetUserVisibleTypes() {
   user_visible_types.Remove(syncer::DICTIONARY);
   user_visible_types.Remove(syncer::EXTENSION_SETTINGS);
   user_visible_types.Remove(syncer::SEARCH_ENGINES);
+  user_visible_types.Remove(syncer::SESSIONS);
+  user_visible_types.Remove(syncer::HISTORY_DELETE_DIRECTIVES);
   return user_visible_types;
 }
 
@@ -118,13 +120,12 @@ TEST_F(SyncPrefsTest, PreferredTypesNotKeepEverythingSynced) {
     if (it.Get() == syncer::EXTENSIONS) {
       expected_preferred_types.Put(syncer::EXTENSION_SETTINGS);
     }
-    if (it.Get() == syncer::SESSIONS) {
+    if (it.Get() == syncer::TYPED_URLS) {
       expected_preferred_types.Put(syncer::HISTORY_DELETE_DIRECTIVES);
+      expected_preferred_types.Put(syncer::SESSIONS);
     }
-    // TODO(akalin): Remove this when history delete directives are
-    // registered by default.
-    if (it.Get() == syncer::HISTORY_DELETE_DIRECTIVES) {
-      expected_preferred_types.Clear();
+    if (it.Get() == syncer::TABS) {
+      expected_preferred_types.Put(syncer::SESSIONS);
     }
     sync_prefs.SetPreferredDataTypes(user_types, preferred_types);
     EXPECT_TRUE(expected_preferred_types.Equals(