Update the window labels if they change in overview mode.

ui/aura/window.h

 // 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.
 
 #ifndef UI_AURA_WINDOW_H_
 #define UI_AURA_WINDOW_H_
 
 #include <map>
 #include <string>
 #include <vector>
@@ skipping 78 matching lines @@
   ui::wm::WindowType type() const { return type_; }
   void SetType(ui::wm::WindowType type);
 
   int id() const { return id_; }
   void set_id(int id) { id_ = id; }
 
   const std::string& name() const { return name_; }
   void SetName(const std::string& name);
 
   const base::string16 title() const { return title_; }
-  void set_title(const base::string16& title) { title_ = title; }
+  void SetTitle(const base::string16& title);
 
   bool transparent() const { return transparent_; }
   void SetTransparent(bool transparent);
 
   // See description in Layer::SetFillsBoundsCompletely.
   void SetFillsBoundsCompletely(bool fills_bounds);
 
   WindowDelegate* delegate() { return delegate_; }
   const WindowDelegate* delegate() const { return delegate_; }
 
@@ skipping 425 matching lines @@
   };
 
   std::map<const void*, Value> prop_map_;
 
   DISALLOW_COPY_AND_ASSIGN(Window);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_H_