mash: Have chrome set itself as the app list presenter.

ui/app_list/presenter/app_list.cc

+// Copyright 2016 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/presenter/app_list.h"
+
+namespace app_list {
+
+AppList::AppList() {}
+
+AppList::~AppList() {}
+
+void AppList::BindRequest(mojom::AppListRequest request) {
+  bindings_.AddBinding(this, std::move(request));
+}
+
+mojom::AppListPresenter* AppList::GetAppListPresenter() {
+  return presenter_.get();
+}
+
+void AppList::SetAppListPresenter(mojom::AppListPresenterPtr presenter) {
+  presenter_ = std::move(presenter);
+}
+
+}  // namespace app_list