Desktop aura: Break aura::Window::SetParent in two.

ui/aura/test/test_windows.h

Index: ui/aura/test/test_windows.h
diff --git a/ui/aura/test/test_windows.h b/ui/aura/test/test_windows.h
index 71dba4511de02e1fc05a3d571af703853a2a69e4..94f3ac677125ce72f13b8363d5364d852ce70216 100644
--- a/ui/aura/test/test_windows.h
+++ b/ui/aura/test/test_windows.h
@@ -16,6 +16,9 @@
 namespace aura {
 namespace test {
 
+// These functions expect a non-NULL parent. If you want to let the
+// StackingClient determine where to place the windows, there are equivalent
+// methods in AshTestBase.
 Window* CreateTestWindowWithId(int id, Window* parent);
 Window* CreateTestWindowWithBounds(const gfx::Rect& bounds, Window* parent);
 Window* CreateTestWindow(SkColor color,
@@ -32,9 +35,6 @@ Window* CreateTestWindowWithDelegateAndType(WindowDelegate* delegate,
                                             const gfx::Rect& bounds,
                                             Window* parent);
 
-// Creates a transient child window of |parent|.
-Window* CreateTransientChild(int id, Window* parent);
-
 // Returns true if |upper| is above |lower| in the window stacking order.
 bool WindowIsAbove(Window* upper, Window* lower);