Use mojo app list interfaces for mash and classic ash.

ash/shell/example_app_list_presenter.h

+// 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.
+
+#ifndef ASH_SHELL_EXAMPLE_APP_LIST_PRESENTER_H_
+#define ASH_SHELL_EXAMPLE_APP_LIST_PRESENTER_H_
+
+#include "ash/app_list/app_list_presenter_delegate_factory.h"
+#include "base/macros.h"
+#include "mojo/public/cpp/bindings/binding.h"
+#include "ui/app_list/presenter/app_list_presenter.mojom.h"
+#include "ui/app_list/presenter/app_list_presenter_impl.h"
+#include "ui/app_list/presenter/test/test_app_list_view_delegate_factory.h"
+
+namespace ash {
+namespace shell {
+
+// An example implementation of AppListPresenter used for ash_shell.

[Daniel Erat, 2016/12/22 18:17:57]

how will this example class be used? is it a stub for tests? should it live
somewhere else?

[msw, 2016/12/23 03:59:34]

Hopefully the comment is clear enough, it's used for ash_shell[_with_content],
which is the example ash shell environment. This is somewhat different than the
implementation used for testing, and certainly different than the implementation
used for Chrome OS. I hope to simplify further down the line; the app_list code
is a mess :(

+class ExampleAppListPresenter : public app_list::mojom::AppListPresenter {
+ public:
+  ExampleAppListPresenter();
+  ~ExampleAppListPresenter() override;
+
+  app_list::mojom::AppListPresenterPtr CreateInterfacePtrAndBind();
+
+  // app_list::mojom::AppListPresenter:
+  void Show(int64_t display_id) override;
+  void Dismiss() override;
+  void ToggleAppList(int64_t display_id) override;
+
+ private:
+  mojo::Binding<app_list::mojom::AppListPresenter> binding_;
+  AppListPresenterDelegateFactory app_list_presenter_delegate_factory_;
+  app_list::AppListPresenterImpl app_list_presenter_impl_;
+
+  DISALLOW_COPY_AND_ASSIGN(ExampleAppListPresenter);
+};
+
+}  // namespace shell
+}  // namespace ash
+
+#endif  // ASH_SHELL_EXAMPLE_APP_LIST_PRESENTER_H_