app_list: Fix app_list_unittests crash.

ui/app_list/apps_grid_view.cc

 // 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.
 
 #include "ui/app_list/apps_grid_view.h"
 
 #include <algorithm>
 
 #include "ui/app_list/app_list_item_view.h"
 #include "ui/app_list/pagination_model.h"
@@ skipping 275 matching lines @@
 
   if (selected_item_index_ >= 0)
     GetItemViewAtIndex(selected_item_index_)->SchedulePaint();
 
   if (index < 0 || index >= child_count()) {
     selected_item_index_ = -1;
   } else {
     selected_item_index_ = index;
     AppListItemView* selected_view = GetItemViewAtIndex(selected_item_index_);
     selected_view->SchedulePaint();
-    GetWidget()->NotifyAccessibilityEvent(
-        selected_view, ui::AccessibilityTypes::EVENT_FOCUS, true);
+    if (GetWidget()) {
+      GetWidget()->NotifyAccessibilityEvent(
+          selected_view, ui::AccessibilityTypes::EVENT_FOCUS, true);
+    }
 
     if (tiles_per_page()) {
       pagination_model_->SelectPage(selected_item_index_ / tiles_per_page(),
                                     true /* animate */);
     }
   }
 }
 
 void AppsGridView::ListItemsAdded(size_t start, size_t count) {
   for (size_t i = start; i < start + count; ++i)
@@ skipping 29 matching lines @@
 void AppsGridView::TransitionChanged() {
   // Update layout for valid page transition only since over-scroll no longer
   // animates app icons.
   const PaginationModel::Transition& transition =
       pagination_model_->transition();
   if (pagination_model_->is_valid_page(transition.target_page))
     Layout();
 }
 
 }  // namespace app_list