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

ash/wm/workspace/multi_window_resize_controller_unittest.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/wm/workspace/multi_window_resize_controller.h"
 
 #include "ash/shell.h"
 #include "ash/test/ash_test_base.h"
 #include "ash/wm/window_util.h"
 #include "ash/wm/workspace_controller.h"
@@ skipping 23 matching lines @@
     resize_controller_ = WorkspaceEventHandlerTestHelper(event_handler).
         resize_controller();
   }
 
  protected:
   aura::Window* CreateTestWindow(aura::WindowDelegate* delegate,
                                  const gfx::Rect& bounds) {
     aura::Window* window = new aura::Window(delegate);
     window->SetType(aura::client::WINDOW_TYPE_NORMAL);
     window->Init(ui::LAYER_TEXTURED);
-    window->SetParent(NULL);
+    SetDefaultParentByPrimaryRootWindow(window);
     window->SetBounds(bounds);
     window->Show();
     return window;
   }
 
   void ShowNow() {
     resize_controller_->ShowNow();
   }
 
   bool IsShowing() {
@@ skipping 193 matching lines @@
   EXPECT_TRUE(HasTarget(w3.get()));
 
   // Release the mouse. The resizer should still be visible and a subsequent
   // press should not trigger a DCHECK.
   generator.ReleaseLeftButton();
   EXPECT_TRUE(IsShowing());
   generator.PressLeftButton();
 }
 }  // namespace internal
 }  // namespace ash