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

ui/aura/window.cc

 // 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.
 
 #include "ui/aura/window.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "base/stl_util.h"
@@ skipping 355 matching lines @@
 bool Window::HasFocus() const {
   const internal::FocusManager* focus_manager = GetFocusManager();
   return focus_manager ? focus_manager->IsFocusedWindow(this) : false;
 }
 
 // For a given window, we determine its focusability by inspecting each sibling
 // after it (i.e. drawn in front of it in the z-order) to see if it stops
 // propagation of events that would otherwise be targeted at windows behind it.
 // We then perform this same check on every window up to the root.
 bool Window::CanFocus() const {
-  // TODO(beng): Figure out how to consult the delegate wrt. focusability also.
-  if (!IsVisible() || !parent_)
+  if (!IsVisible() || !parent_ || (delegate_ && !delegate_->CanFocus()))
     return false;
 
   Windows::const_iterator i = std::find(parent_->children().begin(),
                                         parent_->children().end(),
                                         this);
   for (++i; i != parent_->children().end(); ++i) {
     if ((*i)->StopsEventPropagation())
       return false;
   }
   return parent_->CanFocus();
@@ skipping 166 matching lines @@
 void Window::OnStackingChanged() {
   FOR_EACH_OBSERVER(WindowObserver, observers_, OnWindowStackingChanged(this));
 }
 
 void Window::OnPaintLayer(gfx::Canvas* canvas) {
   if (delegate_)
     delegate_->OnPaint(canvas);
 }
 
 }  // namespace aura