app_list: Fix crash after uninstalling last app.

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 219 matching lines @@
   if (selected_item_index_ >= 0)
     handled = GetItemViewAtIndex(selected_item_index_)->OnKeyReleased(event);
 
   return handled;
 }
 
 void AppsGridView::OnPaintFocusBorder(gfx::Canvas* canvas) {
   // Override to not paint focus frame.
 }
 
+void AppsGridView::ViewHierarchyChanged(bool is_add,
+                                        views::View* parent,
+                                        views::View* child) {
+  if (!is_add) {
+    if (parent == this &&
+        selected_item_index_ >= 0 &&
+        GetItemViewAtIndex(selected_item_index_) == child) {
+      selected_item_index_ = -1;
+    }
+  }
+}
+
 void AppsGridView::Update() {
   selected_item_index_ = -1;
   RemoveAllChildViews(true);
   if (!model_ || model_->item_count() == 0)
     return;
 
   for (size_t i = 0; i < model_->item_count(); ++i)
     AddChildView(CreateViewForItemAtIndex(i));
 
   UpdatePaginationModel();
@@ skipping 69 matching lines @@
 
 void AppsGridView::SelectedPageChanged(int old_selected, int new_selected) {
   Layout();
 }
 
 void AppsGridView::TransitionChanged() {
   Layout();
 }
 
 }  // namespace app_list