Renames aura::client::WindowTreeClient to WindowParentingClient

ui/aura/test/aura_test_helper.h

Index: ui/aura/test/aura_test_helper.h
diff --git a/ui/aura/test/aura_test_helper.h b/ui/aura/test/aura_test_helper.h
index 3a755e06ab4db0caf20c71fb9223fbba1cb89b18..65332f6bd86fc9c6e096f1faf9a963a6c4ad8ade 100644
--- a/ui/aura/test/aura_test_helper.h
+++ b/ui/aura/test/aura_test_helper.h
@@ -32,7 +32,7 @@ class DefaultCaptureClient;
 class FocusClient;
 }
 namespace test {
-class TestWindowTreeClient;
+class TestWindowParentingClient;
 
 // A helper class owned by tests that does common initialization required for
 // Aura use. This class creates a root window with clients and other objects
@@ -64,7 +64,7 @@ class AuraTestHelper {
   bool teardown_called_;
   std::unique_ptr<aura::Env> env_;
   std::unique_ptr<WindowTreeHost> host_;
-  std::unique_ptr<TestWindowTreeClient> stacking_client_;
+  std::unique_ptr<TestWindowParentingClient> parenting_client_;
   std::unique_ptr<client::DefaultCaptureClient> capture_client_;
   std::unique_ptr<client::FocusClient> focus_client_;
   std::unique_ptr<TestScreen> test_screen_;