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

ui/aura/test/test_window_delegate.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/test/test_window_delegate.h"
 
 #include "third_party/skia/include/core/SkCanvas.h"
 #include "ui/aura/event.h"
 #include "ui/aura/window.h"
 #include "ui/base/hit_test.h"
@@ skipping 38 matching lines @@
 }
 
 bool TestWindowDelegate::OnMouseEvent(MouseEvent* event) {
   return false;
 }
 
 ui::TouchStatus TestWindowDelegate::OnTouchEvent(TouchEvent* event) {
   return ui::TOUCH_STATUS_UNKNOWN;
 }
 
+bool TestWindowDelegate::CanFocus() {
+  return true;
+}
+
 bool TestWindowDelegate::ShouldActivate(Event* event) {
   return true;
 }
 
 void TestWindowDelegate::OnActivated() {
 }
 
 void TestWindowDelegate::OnLostActive() {
 }
 
@@ skipping 57 matching lines @@
 }
 void ActivateWindowDelegate::OnActivated() {
   activated_count_++;
 }
 void ActivateWindowDelegate::OnLostActive() {
   lost_active_count_++;
 }
 
 }  // namespace test
 }  // namespace aura