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

ash/wm/workspace/workspace.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/workspace.h"
 
 #include "ash/shell_window_ids.h"
 #include "ash/wm/property_util.h"
 #include "ash/wm/window_animations.h"
 #include "ash/wm/window_properties.h"
@@ skipping 16 matching lines @@
       workspace_layout_manager_(NULL) {
   window_->SetProperty(internal::kChildWindowVisibilityChangesAnimatedKey,
                        true);
   SetWindowVisibilityAnimationTransition(window_, ANIMATE_NONE);
   window_->set_id(kShellWindowId_WorkspaceContainer);
   window_->SetName("WorkspaceContainer");
   window_->Init(ui::LAYER_NOT_DRAWN);
   // Do this so when animating out windows don't extend beyond the bounds.
   window_->layer()->SetMasksToBounds(true);
   window_->Hide();
-  window_->SetParent(parent);
+  parent->AddChild(window_);
   window_->SetProperty(internal::kUsesScreenCoordinatesKey, true);
 
   // The layout-manager cannot be created in the initializer list since it
   // depends on the window to have been initialized.
   workspace_layout_manager_ = new WorkspaceLayoutManager(this);
   window_->SetLayoutManager(workspace_layout_manager_);
 }
 
 Workspace::~Workspace() {
   // ReleaseWindow() should have been invoked before we're deleted.
@@ skipping 38 matching lines @@
          WorkspaceManager::WillRestoreMaximized(child))) {
       if (++count == 2)
         return count;
     }
   }
   return count;
 }
 
 }  // namespace internal
 }  // namespace ash