Fixes bug in handling restacking because of transients

ui/aura/mus/window_tree_client.h

 // Copyright 2014 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.
 
 #ifndef UI_AURA_MUS_WINDOW_TREE_CLIENT_H_
 #define UI_AURA_MUS_WINDOW_TREE_CLIENT_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 401 matching lines @@
   void OnWindowTreeHostBoundsWillChange(WindowTreeHostMus* window_tree_host,
                                         const gfx::Rect& bounds) override;
   std::unique_ptr<WindowPortMus> CreateWindowPortForTopLevel() override;
   void OnWindowTreeHostCreated(WindowTreeHostMus* window_tree_host) override;
 
   // Override from client::TransientWindowClientObserver:
   void OnTransientChildWindowAdded(Window* parent,
                                    Window* transient_child) override;
   void OnTransientChildWindowRemoved(Window* parent,
                                      Window* transient_child) override;
+  void OnWillRestackTransientChildAbove(Window* source,
+                                        Window* window) override;
+  void OnDidRestackTransientChildAbove(Window* source, Window* window) override;
 
   // Overriden from DragDropControllerHost:
   uint32_t CreateChangeIdForDrag(WindowMus* window) override;
 
   // Overrided from CaptureSynchronizerDelegate:
   uint32_t CreateChangeIdForCapture(WindowMus* window) override;
 
   // Overrided from FocusSynchronizerDelegate:
   uint32_t CreateChangeIdForFocus(WindowMus* window) override;
 
@@ skipping 65 matching lines @@
   std::unique_ptr<DragDropControllerMus> drag_drop_controller_;
 
   base::WeakPtrFactory<WindowTreeClient> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeClient);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_MUS_WINDOW_TREE_CLIENT_H_