Refactor ModelTypePayloadMap and ObjectIdPayloadMap to StateMaps.

sync/test/engine/mock_connection_manager.cc

Index: sync/test/engine/mock_connection_manager.cc
diff --git a/sync/test/engine/mock_connection_manager.cc b/sync/test/engine/mock_connection_manager.cc
index 3739bf3ab8a6018ae663b8f28c9e05847c2fa042..0d4041b26f148b3392941d9069998ae8b17ce866 100644
--- a/sync/test/engine/mock_connection_manager.cc
+++ b/sync/test/engine/mock_connection_manager.cc
@@ -408,8 +408,8 @@ void MockConnectionManager::ProcessGetUpdates(
     EXPECT_EQ(expected_filter_.Has(model_type), (progress_marker != NULL))
         << "Syncer requested_types differs from test expectation.";
     if (progress_marker) {
-      EXPECT_EQ((expected_payloads_.count(model_type) > 0 ?
-                 expected_payloads_[model_type] :
+      EXPECT_EQ((expected_states_.count(model_type) > 0 ?
+                 expected_states_[model_type].payload :
                  std::string()),
                 progress_marker->notification_hint());
     }