Revert of mus: Enable system modal windows

components/mus/ws/modal_window_controller.h

Index: components/mus/ws/modal_window_controller.h
diff --git a/components/mus/ws/modal_window_controller.h b/components/mus/ws/modal_window_controller.h
deleted file mode 100644
index 112fce771e64c5d364add2d134e62140a4d9c702..0000000000000000000000000000000000000000
--- a/components/mus/ws/modal_window_controller.h
+++ /dev/null
@@ -1,87 +0,0 @@
-// 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 COMPONENTS_MUS_WS_MODAL_WINDOW_CONTROLLER_H_
-#define COMPONENTS_MUS_WS_MODAL_WINDOW_CONTROLLER_H_
-
-#include <list>
-#include <map>
-
-#include "components/mus/ws/server_window_drawn_tracker_observer.h"
-#include "components/mus/ws/server_window_observer.h"
-
-namespace mus {
-namespace ws {
-
-class EventDispatcher;
-class ServerWindow;
-class ServerWindowDrawnTracker;
-
-namespace test {
-class ModalWindowControllerTestApi;
-}
-
-// Used to keeps track of system modal windows and check whether windows are
-// blocked by modal windows or not to do appropriate retargetting of events.
-class ModalWindowController : public ServerWindowObserver,
-                              public ServerWindowDrawnTrackerObserver {
- public:
-  explicit ModalWindowController(EventDispatcher* event_dispatcher);
-  ~ModalWindowController() override;
-
-  // Adds a system modal window. The window remains modal to system until it is
-  // destroyed. There can exist multiple system modal windows, in which case the
-  // one that is visible and added most recently or shown most recently would be
-  // the active one.
-  void AddSystemModalWindow(ServerWindow* window);
-
-  // Checks whether |modal_window| is a visible modal window that blocks
-  // |window|.
-  bool IsWindowBlockedBy(const ServerWindow* window,
-                         const ServerWindow* modal_window) const;
-
-  // Checks whether |window| is blocked by any visible modal window.
-  bool IsWindowBlocked(const ServerWindow* window) const;
-
-  // Returns the window that events targeted to |window| should be retargeted
-  // to; according to modal windows. If any modal window is blocking |window|
-  // (either system modal or window modal), returns the topmost one; otherwise,
-  // returns |window| itself.
-  const ServerWindow* GetTargetForWindow(const ServerWindow* window) const;
-  ServerWindow* GetTargetForWindow(ServerWindow* window) const {
-    return const_cast<ServerWindow*>(
-        GetTargetForWindow(static_cast<const ServerWindow*>(window)));
-  }
-
- private:
-  friend class test::ModalWindowControllerTestApi;
-
-  // Returns the system modal window that is visible and added/shown most
-  // recently, if any.
-  ServerWindow* GetActiveSystemModalWindow() const;
-
-  // ServerWindowObserver:
-  void OnWindowDestroyed(ServerWindow* window) override;
-
-  // ServerWindowDrawnTrackerObserver:
-  void OnDrawnStateChanged(ServerWindow* ancestor,
-                           ServerWindow* window,
-                           bool is_drawn) override;
-
-  EventDispatcher* event_dispatcher_;
-
-  // List of system modal windows in order they are added/shown.
-  std::list<ServerWindow*> system_modal_windows_;
-
-  // Drawn trackers for system modal windows.
-  std::map<ServerWindow*, std::unique_ptr<ServerWindowDrawnTracker>>
-      window_drawn_trackers_;
-
-  DISALLOW_COPY_AND_ASSIGN(ModalWindowController);
-};
-
-}  // namespace ws
-}  // namespace mus
-
-#endif  // COMPONENTS_MUS_WS_MODAL_WINDOW_CONTROLLER_H_