mash: Migrate ScopedTargetRootWindow to //ash/common

ash/display/screen_position_controller.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/display/screen_position_controller.h"
 
+#include "ash/aura/wm_window_aura.h"
 #include "ash/common/shell_window_ids.h"
 #include "ash/common/wm/window_state.h"
+#include "ash/common/wm_shell.h"
+#include "ash/common/wm_window.h"
 #include "ash/display/window_tree_host_manager.h"
 #include "ash/root_window_controller.h"
 #include "ash/shell.h"
 #include "ash/wm/system_modal_container_layout_manager.h"
 #include "ash/wm/window_properties.h"
 #include "ui/aura/client/capture_client.h"
 #include "ui/aura/client/focus_client.h"
 #include "ui/aura/window.h"
 #include "ui/aura/window_event_dispatcher.h"
 #include "ui/aura/window_tracker.h"
@@ skipping 186 matching lines @@
       window->SetBounds(new_bounds);
 
       dst_container->AddChild(window);
 
       MoveAllTransientChildrenToNewRoot(display, window);
 
       // Restore focused/active window.
       if (tracker.Contains(focused)) {
         aura::client::GetFocusClient(window)->FocusWindow(focused);
         // TODO(beng): replace with GetRootWindow().
-        ash::Shell::GetInstance()->set_target_root_window(
-            focused->GetRootWindow());
+        WmShell::Get()->set_root_window_for_new_windows(
+            WmWindowAura::Get(focused->GetRootWindow()));
       } else if (tracker.Contains(active)) {
         activation_client->ActivateWindow(active);
       }
       // TODO(oshima): We should not have to update the bounds again
       // below in theory, but we currently do need as there is a code
       // that assumes that the bounds will never be overridden by the
       // layout mananger. We should have more explicit control how
       // constraints are applied by the layout manager.
     }
   }
   gfx::Point origin(bounds.origin());
   const gfx::Point display_origin = display::Screen::GetScreen()
                                         ->GetDisplayNearestWindow(window)
                                         .bounds()
                                         .origin();
   origin.Offset(-display_origin.x(), -display_origin.y());
   window->SetBounds(gfx::Rect(origin, bounds.size()));
 }
 
 }  // namespace ash