[Sync] Have SBH tell SyncManager which types to purge

chrome/browser/sync/glue/sync_backend_registrar_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/sync/glue/sync_backend_registrar.h"
 
 #include "chrome/browser/sync/glue/change_processor_mock.h"
 #include "chrome/browser/sync/glue/ui_model_worker.h"
 #include "chrome/test/base/testing_profile.h"
 #include "content/public/test/test_browser_thread.h"
@@ skipping 110 matching lines @@
   EXPECT_TRUE(
       registrar.ConfigureDataTypes(types1, ModelTypeSet()).Equals(types1));
   {
     syncer::ModelSafeRoutingInfo expected_routing_info;
     expected_routing_info[BOOKMARKS] = syncer::GROUP_PASSIVE;
     expected_routing_info[NIGORI] = syncer::GROUP_PASSIVE;
     expected_routing_info[AUTOFILL] = syncer::GROUP_PASSIVE;
     ExpectRoutingInfo(&registrar, expected_routing_info);
   }
   ExpectHasProcessorsForTypes(registrar, ModelTypeSet());
+  EXPECT_TRUE(types1.Equals(registrar.GetLastConfiguredTypes()));
 
   // Add and remove.
   const ModelTypeSet types2(PREFERENCES, THEMES);
   EXPECT_TRUE(registrar.ConfigureDataTypes(types2, types1).Equals(types2));
   {
     syncer::ModelSafeRoutingInfo expected_routing_info;
     expected_routing_info[PREFERENCES] = syncer::GROUP_PASSIVE;
     expected_routing_info[THEMES] = syncer::GROUP_PASSIVE;
     ExpectRoutingInfo(&registrar, expected_routing_info);
   }
   ExpectHasProcessorsForTypes(registrar, ModelTypeSet());
+  EXPECT_TRUE(types2.Equals(registrar.GetLastConfiguredTypes()));
 
   // Remove.
   EXPECT_TRUE(registrar.ConfigureDataTypes(ModelTypeSet(), types2).Empty());
   ExpectRoutingInfo(&registrar, syncer::ModelSafeRoutingInfo());
   ExpectHasProcessorsForTypes(registrar, ModelTypeSet());
+  EXPECT_TRUE(ModelTypeSet().Equals(registrar.GetLastConfiguredTypes()));
 
   registrar.OnSyncerShutdownComplete();
   registrar.StopOnUIThread();
 }
 
 void TriggerChanges(SyncBackendRegistrar* registrar, ModelType type) {
   registrar->OnChangesApplied(type, 0, NULL,
                               syncer::ImmutableChangeRecordList());
   registrar->OnChangesComplete(type);
 }
@@ skipping 87 matching lines @@
   // Should do nothing.
   TriggerChanges(&registrar, AUTOFILL);
 
   registrar.OnSyncerShutdownComplete();
   registrar.StopOnUIThread();
 }
 
 }  // namespace
 
 }  // namespace browser_sync