[Sync] Have configuration specify which datatypes are ready to sync

chrome/browser/sync/glue/sync_backend_host_mock.cc

Index: chrome/browser/sync/glue/sync_backend_host_mock.cc
diff --git a/chrome/browser/sync/glue/sync_backend_host_mock.cc b/chrome/browser/sync/glue/sync_backend_host_mock.cc
index 7d1fc7c3f4fe7c11aad1ff5fa3bcf81962fe596e..1c8244ed1799e4b6332e0009591b34b9aa7dc3d7 100644
--- a/chrome/browser/sync/glue/sync_backend_host_mock.cc
+++ b/chrome/browser/sync/glue/sync_backend_host_mock.cc
@@ -55,12 +55,14 @@ scoped_ptr<base::Thread> SyncBackendHostMock::Shutdown(
 
 void SyncBackendHostMock::UnregisterInvalidationIds() {}
 
-void SyncBackendHostMock::ConfigureDataTypes(
+syncer::ModelTypeSet SyncBackendHostMock::ConfigureDataTypes(
     syncer::ConfigureReason reason,
     const DataTypeConfigStateMap& config_state_map,
-    const base::Callback<void(syncer::ModelTypeSet,
-                              syncer::ModelTypeSet)>& ready_task,
-    const base::Callback<void()>& retry_callback) {}
+    const base::Callback<void(syncer::ModelTypeSet, syncer::ModelTypeSet)>&
+        ready_task,
+    const base::Callback<void()>& retry_callback) {
+  return syncer::ModelTypeSet();
+}
 
 void SyncBackendHostMock::EnableEncryptEverything() {}