Revert 115515 - [Aura] Implement views-based applist.

ui/aura_shell/app_list/app_list_model.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_shell/app_list/app_list_model.h"
-
-namespace aura_shell {
-
-AppListModel::AppListModel() {
-}
-
-AppListModel::~AppListModel() {
-}
-
-void AppListModel::AddGroup(AppListItemGroupModel* group) {
-  groups_.Add(group);
-}
-
-AppListItemGroupModel* AppListModel::GetGroup(int index) {
-  DCHECK(index >= 0 && index < group_count());
-  return groups_.item_at(index);
-}
-
-void AppListModel::AddObserver(ui::ListModelObserver* observer) {
-  groups_.AddObserver(observer);
-}
-
-void AppListModel::RemoveObserver(ui::ListModelObserver* observer) {
-  groups_.RemoveObserver(observer);
-}
-
-}  // namespace aura_shell