Moves management of transients out of Window

ui/aura/test/aura_test_base.h

Index: ui/aura/test/aura_test_base.h
diff --git a/ui/aura/test/aura_test_base.h b/ui/aura/test/aura_test_base.h
index 52cccf068b74c86f97a2526fb5c330a06068f8ea..971fdba223d13e89be695c494b8f9f7e695527d3 100644
--- a/ui/aura/test/aura_test_base.h
+++ b/ui/aura/test/aura_test_base.h
@@ -32,9 +32,6 @@ class AuraTestBase : public testing::Test {
   aura::Window* CreateNormalWindow(int id, Window* parent,
                                    aura::WindowDelegate* delegate);
 
-  // Creates a transient window that is transient to |parent|.
-  aura::Window* CreateTransientChild(int id, aura::Window* parent);
-
  protected:
   void RunAllPendingInMessageLoop();