Desktop Aura: Allow tab drags out of window.

ui/aura/root_window_host_delegate.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_ROOT_WINDOW_HOST_DELEGATE_H_
 #define UI_AURA_ROOT_WINDOW_HOST_DELEGATE_H_
 
 namespace gfx {
+class Point;
 class Size;
 }
 
 namespace ui {
 class KeyEvent;
 class MouseEvent;
 class ScrollEvent;
 class TouchEvent;
 }
 
 namespace aura {
 
 class RootWindow;
 
 // A private interface used by RootWindowHost implementations to communicate
 // with their owning RootWindow.
 class AURA_EXPORT RootWindowHostDelegate {
  public:
   virtual bool OnHostKeyEvent(ui::KeyEvent* event) = 0;
   virtual bool OnHostMouseEvent(ui::MouseEvent* event) = 0;
   virtual bool OnHostScrollEvent(ui::ScrollEvent* event) = 0;
   virtual bool OnHostTouchEvent(ui::TouchEvent* event) = 0;
 
   virtual void OnHostLostCapture() = 0;
 
   virtual void OnHostPaint() = 0;
 
+  virtual void OnHostMoved(const gfx::Point& origin) = 0;
   virtual void OnHostResized(const gfx::Size& size) = 0;
 
   virtual float GetDeviceScaleFactor() = 0;
 
   virtual RootWindow* AsRootWindow() = 0;
 
  protected:
   virtual ~RootWindowHostDelegate() {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_ROOT_WINDOW_HOST_DELEGATE_H_