[Sync] Update SyncBackendHost to forward ClearServerData to SyncManager

sync/internal_api/sync_manager_impl_unittest.cc

Index: sync/internal_api/sync_manager_impl_unittest.cc
diff --git a/sync/internal_api/sync_manager_impl_unittest.cc b/sync/internal_api/sync_manager_impl_unittest.cc
index 84389e639c7b2370060dbbda5255be150cc63661..e276a735bf0445f92197d809708eeabb522ee525 100644
--- a/sync/internal_api/sync_manager_impl_unittest.cc
+++ b/sync/internal_api/sync_manager_impl_unittest.cc
@@ -2661,6 +2661,16 @@ TEST_F(SyncManagerTestWithMockScheduler, ReConfiguration) {
       ProtocolTypes()).Equals(disabled_types));
 }
 
+// Test that SyncManager::ClearServerData invokes the scheduler.
+TEST_F(SyncManagerTestWithMockScheduler, ClearServerData) {
+  EXPECT_CALL(*scheduler(), Start(SyncScheduler::CLEAR_SERVER_DATA_MODE, _));
+  CallbackCounter callback_counter;
+  sync_manager_.ClearServerData(base::Bind(
+      &CallbackCounter::Callback, base::Unretained(&callback_counter)));
+  PumpLoop();
+  EXPECT_EQ(1, callback_counter.times_called());
+}
+
 // Test that PurgePartiallySyncedTypes purges only those types that have not
 // fully completed their initial download and apply.
 TEST_F(SyncManagerTest, PurgePartiallySyncedTypes) {