aura: Ask the WindowDelegate before a Window is Focus()ed.

ui/aura/window_delegate.h

 // Copyright (c) 2011 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_DELEGATE_H_
 #define UI_AURA_WINDOW_DELEGATE_H_
 #pragma once
 
 #include "ui/aura/aura_export.h"
 #include "ui/base/events.h"
@@ skipping 40 matching lines @@
   virtual bool OnMouseEvent(MouseEvent* event) = 0;
 
   virtual ui::TouchStatus OnTouchEvent(TouchEvent* event) = 0;
 
   // Returns true if the window should be activated. |event| is either the mouse
   // event supplied if the activation is the result of a mouse, or the touch
   // event if the activation is the result of a touch, or NULL if activation is
   // attempted for another reason.
   virtual bool ShouldActivate(Event* event) = 0;
 
+  // Returns true of the window can be focused.
+  virtual bool CanFocus() { return true; }

[sadrul, 2011/12/01 21:48:03]

This probably should be pure virtual?

[Ben Goodger (Google), 2011/12/01 22:16:31]

Yes it should. In general, when you are adding the first non-pure virtual method
to an interface, ur doin' it rong.

[sadrul, 2011/12/01 22:18:23]

Yes :) I wanted to confirm the approach looks sane. I will update the patch to
add purity

[sadrul, 2011/12/02 02:25:55]

Done.

+
   // Sent when the window is activated.
   virtual void OnActivated() = 0;
 
   // Sent when the window loses active status.
   virtual void OnLostActive() = 0;
 
   // Invoked when mouse capture is lost on the window.
   virtual void OnCaptureLost() = 0;
 
   // Asks the delegate to paint window contents into the supplied canvas.
@@ skipping 12 matching lines @@
   // Called when the visibility of a Window changed.
   virtual void OnWindowVisibilityChanged(bool visible) = 0;
 
  protected:
   virtual ~WindowDelegate() {}
 };
 
 }  // namespace aura
 
 #endif  // UI_AURA_WINDOW_DELEGATE_H_