Make browser windows override_redirect when dragging tabs.

ui/aura/window_tree_host.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_TREE_HOST_H_
 #define UI_AURA_WINDOW_TREE_HOST_H_
 
 #include <vector>
 
 #include "base/event_types.h"
@@ skipping 39 matching lines @@
   static WindowTreeHost* Create(const gfx::Rect& bounds);
 
   // Returns the WindowTreeHost for the specified accelerated widget, or NULL
   // if there is none associated.
   static WindowTreeHost* GetForAcceleratedWidget(gfx::AcceleratedWidget widget);
 
   void InitHost();
 
   void InitCompositor();
 
+  virtual void RemapWindow() = 0;

[Daniel Erat, 2015/12/28 21:33:02]

nit: move this down to the other similar pure virtual methods below. if it's
only relevant to a particular platform or build configuration, it'd probably
make sense to #ifdef the declaration so you don't end up with a bunch of no-op
implementations on other platforms.

[stapelberg, 2016/01/18 17:22:23]

Done.

+
   void AddObserver(WindowTreeHostObserver* observer);
   void RemoveObserver(WindowTreeHostObserver* observer);
 
   Window* window() { return window_; }
   const Window* window() const { return window_; }
 
   ui::EventProcessor* event_processor();
 
   WindowEventDispatcher* dispatcher() {
     return const_cast<WindowEventDispatcher*>(
@@ skipping 170 matching lines @@
 
   // Whether the InputMethod instance is owned by this WindowTreeHost.
   bool owned_input_method_;
 
   DISALLOW_COPY_AND_ASSIGN(WindowTreeHost);
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_TREE_HOST_H_